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Nowacka A, Getz AM, Bessa-Neto D, Choquet D. Activity-dependent diffusion trapping of AMPA receptors as a key step for expression of early LTP. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230220. [PMID: 38853553 PMCID: PMC11343219 DOI: 10.1098/rstb.2023.0220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Revised: 04/10/2024] [Accepted: 04/11/2024] [Indexed: 06/11/2024] Open
Abstract
This review focuses on the activity-dependent diffusion trapping of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) as a crucial mechanism for the expression of early long-term potentiation (LTP), a process central to learning and memory. Despite decades of research, the precise mechanisms by which LTP induction leads to an increase in AMPAR responses at synapses have been elusive. We review the different hypotheses that have been put forward to explain the increased AMPAR responsiveness during LTP. We discuss the dynamic nature of AMPAR complexes, including their constant turnover and activity-dependent modifications that affect their synaptic accumulation. We highlight a hypothesis suggesting that AMPARs are diffusively trapped at synapses through activity-dependent interactions with protein-based binding slots in the post-synaptic density (PSD), offering a potential explanation for the increased synaptic strength during LTP. Furthermore, we outline the challenges still to be addressed before we fully understand the functional roles and molecular mechanisms of AMPAR dynamic nanoscale organization in LTP. This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.
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Affiliation(s)
- Agata Nowacka
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, BordeauxF-33000, France
| | - Angela M. Getz
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, BordeauxF-33000, France
- University of Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4, BordeauxF-33000, France
| | - Diogo Bessa-Neto
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, BordeauxF-33000, France
| | - Daniel Choquet
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, BordeauxF-33000, France
- University of Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4, BordeauxF-33000, France
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2
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Metzbower SR, Levy AD, Dharmasri PA, Anderson MC, Blanpied TA. Distinct SAP102 and PSD-95 Nano-organization Defines Multiple Types of Synaptic Scaffold Protein Domains at Single Synapses. J Neurosci 2024; 44:e1715232024. [PMID: 38777601 PMCID: PMC11211720 DOI: 10.1523/jneurosci.1715-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 04/30/2024] [Accepted: 05/05/2024] [Indexed: 05/25/2024] Open
Abstract
MAGUK scaffold proteins play a central role in maintaining and modulating synaptic signaling, providing a framework to retain and position receptors, signaling molecules, and other synaptic components. In particular, the MAGUKs SAP102 and PSD-95 are essential for synaptic function at distinct developmental timepoints and perform both overlapping and unique roles. While their similar structures allow for common binding partners, SAP102 is expressed earlier in synapse development and is required for synaptogenesis, whereas PSD-95 expression peaks later and is associated with synapse maturation. PSD-95 and other key synaptic proteins organize into subsynaptic nanodomains that have a significant impact on synaptic transmission, but the nanoscale organization of SAP102 is unknown. How SAP102 is organized within the synapse, and how it relates spatially to PSD-95 on a nanometer scale, could underlie its unique functions and impact how SAP102 scaffolds synaptic proteins. Here we used DNA-PAINT super-resolution microscopy to measure SAP102 nano-organization and its spatial relationship to PSD-95 at individual synapses in mixed-sex rat cultured neurons. We found that like PSD-95, SAP102 accumulates in high-density subsynaptic nanoclusters (NCs). However, SAP102 NCs were smaller and denser than PSD-95 NCs across development. Additionally, only a subset of SAP102 NCs co-organized with PSD-95, revealing MAGUK nanodomains within individual synapses containing either one or both proteins. These MAGUK nanodomain types had distinct NC properties and were differentially enriched with the presynaptic release protein Munc13-1. This organization into both shared and distinct subsynaptic nanodomains may underlie the ability of SAP102 and PSD-95 to perform both common and unique synaptic functions.
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Affiliation(s)
- Sarah R Metzbower
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Aaron D Levy
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Poorna A Dharmasri
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Michael C Anderson
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Thomas A Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland 21201
- University of Maryland Medicine Institute for Neuroscience Discovery, University of Maryland School of Medicine, Baltimore, Maryland 21201
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3
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Fukata Y, Fukata M, MacGillavry HD, Nair D, Hosy E. Celebrating the Birthday of AMPA Receptor Nanodomains: Illuminating the Nanoscale Organization of Excitatory Synapses with 10 Nanocandles. J Neurosci 2024; 44:e2104232024. [PMID: 38839340 PMCID: PMC11154862 DOI: 10.1523/jneurosci.2104-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 04/02/2024] [Accepted: 04/03/2024] [Indexed: 06/07/2024] Open
Abstract
A decade ago, in 2013, and over the course of 4 summer months, three separate observations were reported that each shed light independently on a new molecular organization that fundamentally reshaped our perception of excitatory synaptic transmission (Fukata et al., 2013; MacGillavry et al., 2013; Nair et al., 2013). This discovery unveiled an intricate arrangement of AMPA-type glutamate receptors and their principal scaffolding protein PSD-95, at synapses. This breakthrough was made possible, thanks to advanced super-resolution imaging techniques. It fundamentally changed our understanding of excitatory synaptic architecture and paved the way for a brand-new area of research. In this Progressions article, the primary investigators of the nanoscale organization of synapses have come together to chronicle the tale of their discovery. We recount the initial inquiry that prompted our research, the preceding studies that inspired our work, the technical obstacles that were encountered, and the breakthroughs that were made in the subsequent decade in the realm of nanoscale synaptic transmission. We review the new discoveries made possible by the democratization of super-resolution imaging techniques in the field of excitatory synaptic physiology and architecture, first by the extension to other glutamate receptors and to presynaptic proteins and then by the notion of trans-synaptic organization. After describing the organizational modifications occurring in various pathologies, we discuss briefly the latest technical developments made possible by super-resolution imaging and emerging concepts in synaptic physiology.
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Affiliation(s)
- Yuko Fukata
- Division of Molecular and Cellular Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
- Division of Membrane Physiology, Department of Molecular and Cellular Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
| | - Masaki Fukata
- Division of Membrane Physiology, Department of Molecular and Cellular Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
- Division of Neuropharmacology, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
- Department of Physiological Sciences, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
| | - Harold D MacGillavry
- Division of Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht 3584 CH, The Netherlands
| | - Deepak Nair
- Centre for Neuroscience, Indian Institute of Science, Bangalore 560012, Karnataka, India
| | - Eric Hosy
- Interdisciplinary Institute for Neuroscience, University of Bordeaux, CNRS UMR5297, Bordeaux F-33000, France
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Kaizuka T, Takumi T. Alteration of synaptic protein composition during developmental synapse maturation. Eur J Neurosci 2024; 59:2894-2914. [PMID: 38571321 DOI: 10.1111/ejn.16304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 01/02/2024] [Accepted: 02/07/2024] [Indexed: 04/05/2024]
Abstract
The postsynaptic density (PSD) is a collection of specialized proteins assembled beneath the postsynaptic membrane of dendritic spines. The PSD proteome comprises ~1000 proteins, including neurotransmitter receptors, scaffolding proteins and signalling enzymes. Many of these proteins have essential roles in synaptic function and plasticity. During brain development, changes are observed in synapse density and in the stability and shape of spines, reflecting the underlying molecular maturation of synapses. Synaptic protein composition changes in terms of protein abundance and the assembly of protein complexes, supercomplexes and the physical organization of the PSD. Here, we summarize the developmental alterations of postsynaptic protein composition during synapse maturation. We describe major PSD proteins involved in postsynaptic signalling that regulates synaptic plasticity and discuss the effect of altered expression of these proteins during development. We consider the abnormality of synaptic profiles and synaptic protein composition in the brain in neurodevelopmental disorders such as autism spectrum disorders. We also explain differences in synapse development between rodents and primates in terms of synaptic profiles and protein composition. Finally, we introduce recent findings related to synaptic diversity and nanoarchitecture and discuss their impact on future research. Synaptic protein composition can be considered a major determinant and marker of synapse maturation in normality and disease.
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Affiliation(s)
- Takeshi Kaizuka
- Department of Physiology and Cell Biology, Kobe University School of Medicine, Kobe, Japan
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Toru Takumi
- Department of Physiology and Cell Biology, Kobe University School of Medicine, Kobe, Japan
- RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
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Liu S, Yang X, Yuan M, Wang S, Fan H, Zou Q, Pu Y, Cai Z. High salt diet induces cognitive impairment and is linked to the activation of IGF1R/mTOR/p70S6K signaling. Metab Brain Dis 2024; 39:803-819. [PMID: 38771412 DOI: 10.1007/s11011-024-01358-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 05/06/2024] [Indexed: 05/22/2024]
Abstract
A high-salt diet (HSD) has been associated with various health issues, including hypertension and cardiovascular diseases. However, recent studies have revealed a potential link between high salt intake and cognitive impairment. This study aims to investigate the effects of high salt intake on autophagy, tau protein hyperphosphorylation, and synaptic function and their potential associations with cognitive impairment. To explore these mechanisms, 8-month-old male C57BL/6 mice were fed either a normal diet (0.4% NaCl) or an HSD (8% NaCl) for 3 months, and Neuro-2a cells were incubated with normal medium or NaCl medium (80 mM). Behavioral tests revealed learning and memory deficits in mice fed the HSD. We further discovered that the HSD decreased autophagy, as indicated by diminished levels of the autophagy-associated proteins Beclin-1 and LC3, along with an elevated p62 protein level. HSD feeding significantly decreased insulin-like growth factor-1 receptor (IGF1R) expression in the brain of C57BL/6 mice and activated mechanistic target of rapamycin (mTOR) signaling. In addition, the HSD reduced synaptophysin and postsynaptic density protein 95 (PSD95) expression in the hippocampus and caused synaptic loss in mice. We also found amyloid β accumulation and hyperphosphorylation of tau protein at different loci both in vivo and in vitro. Overall, this study highlights the clinical significance of understanding the impact of an HSD on cognitive function. By targeting the IGF1R/mTOR/p70S6K pathway or promoting autophagy, it may be possible to mitigate the negative effects of high salt intake on cognitive function.
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Affiliation(s)
- Shu Liu
- Chongqing Medical University, 400042, Chongqing, China
- Chongqing institute Green and Intelligent Technology, Chinese Academy of Sciences, 400714, Chongqing, Chongqing, China
- Chongqing School, University of Chinese Academy of Sciences, 400714, Chongqing, Chongqing, China
- Department of Neurology, Chongqing General Hospital, 400013, Chongqing, Chongqing, China
| | - Xu Yang
- Department of Neurology, Chongqing General Hospital, 400013, Chongqing, Chongqing, China
- Department of Neurology, Affiliated Hospital of Southwest Medical University, 646000, Sichuan, China
| | - Minghao Yuan
- Chongqing Medical University, 400042, Chongqing, China
- Chongqing institute Green and Intelligent Technology, Chinese Academy of Sciences, 400714, Chongqing, Chongqing, China
- Chongqing School, University of Chinese Academy of Sciences, 400714, Chongqing, Chongqing, China
- Department of Neurology, Chongqing General Hospital, 400013, Chongqing, Chongqing, China
| | - Shengyuan Wang
- Chongqing Medical University, 400042, Chongqing, China
- Chongqing institute Green and Intelligent Technology, Chinese Academy of Sciences, 400714, Chongqing, Chongqing, China
- Chongqing School, University of Chinese Academy of Sciences, 400714, Chongqing, Chongqing, China
- Department of Neurology, Chongqing General Hospital, 400013, Chongqing, Chongqing, China
| | - Haixia Fan
- Chongqing Medical University, 400042, Chongqing, China
- Chongqing institute Green and Intelligent Technology, Chinese Academy of Sciences, 400714, Chongqing, Chongqing, China
- Chongqing School, University of Chinese Academy of Sciences, 400714, Chongqing, Chongqing, China
- Department of Neurology, Chongqing General Hospital, 400013, Chongqing, Chongqing, China
| | - Qian Zou
- Department of Neurology, Chongqing General Hospital, 400013, Chongqing, Chongqing, China
| | - Yinshuang Pu
- Department of Neurology, Chongqing General Hospital, 400013, Chongqing, Chongqing, China
| | - Zhiyou Cai
- Chongqing Medical University, 400042, Chongqing, China.
- Chongqing institute Green and Intelligent Technology, Chinese Academy of Sciences, 400714, Chongqing, Chongqing, China.
- Chongqing School, University of Chinese Academy of Sciences, 400714, Chongqing, Chongqing, China.
- Department of Neurology, Chongqing General Hospital, 400013, Chongqing, Chongqing, China.
- Department of Neurology, Chongqing Medical University, No. 1, Medical College Road, Yuzhong District, 400016, Chongqing, Chongqing, China.
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6
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Dharmasri PA, Levy AD, Blanpied TA. Differential nanoscale organization of excitatory synapses onto excitatory vs. inhibitory neurons. Proc Natl Acad Sci U S A 2024; 121:e2315379121. [PMID: 38625946 PMCID: PMC11047112 DOI: 10.1073/pnas.2315379121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 03/14/2024] [Indexed: 04/18/2024] Open
Abstract
A key feature of excitatory synapses is the existence of subsynaptic protein nanoclusters (NCs) whose precise alignment across the cleft in a transsynaptic nanocolumn influences the strength of synaptic transmission. However, whether nanocolumn properties vary between excitatory synapses functioning in different cellular contexts is unknown. We used a combination of confocal and DNA-PAINT super-resolution microscopy to directly compare the organization of shared scaffold proteins at two important excitatory synapses-those forming onto excitatory principal neurons (Ex→Ex synapses) and those forming onto parvalbumin-expressing interneurons (Ex→PV synapses). As in Ex→Ex synapses, we find that in Ex→PV synapses, presynaptic Munc13-1 and postsynaptic PSD-95 both form NCs that demonstrate alignment, underscoring synaptic nanostructure and the transsynaptic nanocolumn as conserved organizational principles of excitatory synapses. Despite the general conservation of these features, we observed specific differences in the characteristics of pre- and postsynaptic Ex→PV nanostructure. Ex→PV synapses contained larger PSDs with fewer PSD-95 NCs when accounting for size than Ex→Ex synapses. Furthermore, the PSD-95 NCs were larger and denser. The identity of the postsynaptic cell was also represented in Munc13-1 organization, as Ex→PV synapses hosted larger Munc13-1 puncta that contained less dense but larger and more numerous Munc13-1 NCs. Moreover, we measured the spatial variability of transsynaptic alignment in these synapse types, revealing protein alignment in Ex→PV synapses over a distinct range of distances compared to Ex→Ex synapses. We conclude that while general principles of nanostructure and alignment are shared, cell-specific elements of nanodomain organization likely contribute to functional diversity of excitatory synapses.
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Affiliation(s)
- Poorna A. Dharmasri
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD21201
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD21201
- University of Maryland-Medicine Institute of Neuroscience Discovery, University of Maryland School of Medicine, Baltimore, MD21201
| | - Aaron D. Levy
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD21201
- University of Maryland-Medicine Institute of Neuroscience Discovery, University of Maryland School of Medicine, Baltimore, MD21201
| | - Thomas A. Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD21201
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD21201
- University of Maryland-Medicine Institute of Neuroscience Discovery, University of Maryland School of Medicine, Baltimore, MD21201
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7
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Carretero-Guillén A, Treviño M, Gómez-Climent MÁ, Dogbevia GK, Bertocchi I, Sprengel R, Larkum ME, Vlachos A, Gruart A, Delgado-García JM, Hasan MT. Dentate gyrus is needed for memory retrieval. Mol Psychiatry 2024:10.1038/s41380-024-02546-0. [PMID: 38609585 DOI: 10.1038/s41380-024-02546-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 03/03/2024] [Accepted: 03/26/2024] [Indexed: 04/14/2024]
Abstract
The hippocampus is crucial for acquiring and retrieving episodic and contextual memories. In previous studies, the inactivation of dentate gyrus (DG) neurons by chemogenetic- and optogenetic-mediated hyperpolarization led to opposing conclusions about DG's role in memory retrieval. One study used Designer Receptors Exclusively Activated by Designer Drugs (DREADD)-mediated clozapine N-oxide (CNO)-induced hyperpolarization and reported that the previously formed memory was erased, thus concluding that denate gyrus is needed for memory maintenance. The other study used optogenetic with halorhodopsin induced hyperpolarization and reported and dentate gyrus is needed for memory retrieval. We hypothesized that this apparent discrepancy could be due to the length of hyperpolarization in previous studies; minutes by optogenetics and several hours by DREADD/CNO. Since hyperpolarization interferes with anterograde and retrograde neuronal signaling, it is possible that the memory engram in the dentate gyrus and the entorhinal to hippocampus trisynaptic circuit was erased by long-term, but not with short-term hyperpolarization. We developed and applied an advanced chemogenetic technology to selectively silence synaptic output by blocking neurotransmitter release without hyperpolarizing DG neurons to explore this apparent discrepancy. We performed in vivo electrophysiology during trace eyeblink in a rabbit model of associative learning. Our work shows that the DG output is required for memory retrieval. Based on previous and recent findings, we propose that the actively functional anterograde and retrograde neuronal signaling is necessary to preserve synaptic memory engrams along the entorhinal cortex to the hippocampal trisynaptic circuit.
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Affiliation(s)
- Alejandro Carretero-Guillén
- Division of Neuroscience, University Pablo de Olavide, Seville, Spain
- Achucarro Basque Center for Neuroscience, Leioa, Spain
| | - Mario Treviño
- Max Planck Institute for Medical Research, Heidelberg, Germany
- Instituto de Neurociencias, Universidad de Guadalajara, Guadalajara, 44130, México
| | | | - Godwin K Dogbevia
- Max Planck Institute for Medical Research, Heidelberg, Germany
- Health Canada, Ottawa, ON, Canada
| | - Ilaria Bertocchi
- Max Planck Institute for Medical Research, Heidelberg, Germany
- Neuroscience Institute Cavalieri-Ottolenghi (NICO), University of Turin, Turin, Italy
| | - Rolf Sprengel
- Max Planck Institute for Medical Research, Heidelberg, Germany
| | | | | | - Agnès Gruart
- Division of Neuroscience, University Pablo de Olavide, Seville, Spain
| | | | - Mazahir T Hasan
- Achucarro Basque Center for Neuroscience, Leioa, Spain.
- Max Planck Institute for Medical Research, Heidelberg, Germany.
- NeuroCure, Charité - Universitätsmedizin, Berlin, Germany.
- Ikerbasque - Basque Foundation for Science, Bilbao, Spain.
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8
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Clavet-Fournier V, Lee C, Wegner W, Brose N, Rhee J, Willig KI. Pre- and postsynaptic nanostructures increase in size and complexity after induction of long-term potentiation. iScience 2024; 27:108679. [PMID: 38213627 PMCID: PMC10783556 DOI: 10.1016/j.isci.2023.108679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 11/09/2023] [Accepted: 12/05/2023] [Indexed: 01/13/2024] Open
Abstract
Synapses, specialized contact sites between neurons, are the fundamental elements of neuronal information transfer. Synaptic plasticity involves changes in synaptic morphology and the number of neurotransmitter receptors, and is thought to underlie learning and memory. However, it is not clear how these structural and functional changes are connected. We utilized time-lapse super-resolution STED microscopy of organotypic hippocampal brain slices and cultured neurons to visualize structural changes of the synaptic nano-organization of the postsynaptic scaffolding protein PSD95, the presynaptic scaffolding protein Bassoon, and the GluA2 subunit of AMPA receptors by chemically induced long-term potentiation (cLTP) at the level of single synapses. We found that the nano-organization of all three proteins increased in complexity and size after cLTP induction. The increase was largely synchronous, peaking at ∼60 min after stimulation. Therefore, both the size and complexity of individual pre- and post-synaptic nanostructures serve as substrates for tuning and determining synaptic strength.
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Affiliation(s)
- Valérie Clavet-Fournier
- Group of Optical Nanoscopy in Neuroscience, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Göttingen Graduate Center for Neurosciences, Biophysics, und Molecular Biosciences (GGNB), Göttingen, Germany
| | - ChungKu Lee
- Department of Molecular Neurobiology, Synaptic Physiology Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Waja Wegner
- Group of Optical Nanoscopy in Neuroscience, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany
| | - Nils Brose
- Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - JeongSeop Rhee
- Department of Molecular Neurobiology, Synaptic Physiology Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Katrin I. Willig
- Group of Optical Nanoscopy in Neuroscience, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany
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9
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Dharmasri PA, DeMarco EM, Anderson MC, Levy AD, Blanpied TA. Loss of postsynaptic NMDARs drives nanoscale reorganization of Munc13-1 and PSD-95. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.12.574705. [PMID: 38260705 PMCID: PMC10802569 DOI: 10.1101/2024.01.12.574705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Nanoscale protein organization within the active zone (AZ) and post-synaptic density (PSD) influences synaptic transmission. Nanoclusters of presynaptic Munc13-1 are associated with readily releasable pool size and neurotransmitter vesicle priming, while postsynaptic PSD-95 nanoclusters coordinate glutamate receptors across from release sites to control their opening probability. Nanocluster number, size, and protein density vary between synapse types and with development and plasticity, supporting a wide range of functional states at the synapse. Whether or how the receptors themselves control this critical architecture remains unclear. One prominent PSD molecular complex is the NMDA receptor (NMDAR). NMDARs coordinate several modes of signaling within synapses, giving them the potential to influence synaptic organization through direct protein interactions or through signaling. We found that loss of NMDARs results in larger synapses that contain smaller, denser, and more numerous PSD-95 nanoclusters. Intriguingly, NMDAR loss also generates retrograde reorganization of the active zone, resulting in denser, more numerous Munc13-1 nanoclusters, more of which are aligned with PSD-95 nanoclusters. Together, these changes to synaptic nanostructure predict stronger AMPA receptor-mediated transmission in the absence of NMDARs. Notably, while prolonged antagonism of NMDAR activity increases Munc13-1 density within nanoclusters, it does not fully recapitulate these trans-synaptic effects. Thus, our results confirm that NMDARs play an important role in maintaining pre- and postsynaptic nanostructure and suggest that both decreased NMDAR expression and suppressed NMDAR activity may exert distinct effects on synaptic function, yet through unique architectural mechanisms.
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Affiliation(s)
- Poorna A Dharmasri
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- University of Maryland Medicine Institute of Neuroscience Discovery, Baltimore, MD, USA
- Current address: Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Emily M DeMarco
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- University of Maryland Medicine Institute of Neuroscience Discovery, Baltimore, MD, USA
| | - Michael C Anderson
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- University of Maryland Medicine Institute of Neuroscience Discovery, Baltimore, MD, USA
| | - Aaron D Levy
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- University of Maryland Medicine Institute of Neuroscience Discovery, Baltimore, MD, USA
| | - Thomas A Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- University of Maryland Medicine Institute of Neuroscience Discovery, Baltimore, MD, USA
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10
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Rimbault C, Breillat C, Compans B, Toulmé E, Vicente FN, Fernandez-Monreal M, Mascalchi P, Genuer C, Puente-Muñoz V, Gauthereau I, Hosy E, Claverol S, Giannone G, Chamma I, Mackereth CD, Poujol C, Choquet D, Sainlos M. Engineering paralog-specific PSD-95 recombinant binders as minimally interfering multimodal probes for advanced imaging techniques. eLife 2024; 13:e69620. [PMID: 38167295 PMCID: PMC10803022 DOI: 10.7554/elife.69620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 12/04/2023] [Indexed: 01/05/2024] Open
Abstract
Despite the constant advances in fluorescence imaging techniques, monitoring endogenous proteins still constitutes a major challenge in particular when considering dynamics studies or super-resolution imaging. We have recently evolved specific protein-based binders for PSD-95, the main postsynaptic scaffold proteins at excitatory synapses. Since the synthetic recombinant binders recognize epitopes not directly involved in the target protein activity, we consider them here as tools to develop endogenous PSD-95 imaging probes. After confirming their lack of impact on PSD-95 function, we validated their use as intrabody fluorescent probes. We further engineered the probes and demonstrated their usefulness in different super-resolution imaging modalities (STED, PALM, and DNA-PAINT) in both live and fixed neurons. Finally, we exploited the binders to enrich at the synapse genetically encoded calcium reporters. Overall, we demonstrate that these evolved binders constitute a robust and efficient platform to selectively target and monitor endogenous PSD-95 using various fluorescence imaging techniques.
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Affiliation(s)
- Charlotte Rimbault
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297BordeauxFrance
| | - Christelle Breillat
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297BordeauxFrance
| | - Benjamin Compans
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297BordeauxFrance
| | - Estelle Toulmé
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297BordeauxFrance
| | - Filipe Nunes Vicente
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297BordeauxFrance
| | - Monica Fernandez-Monreal
- University of Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4BordeauxFrance
| | - Patrice Mascalchi
- University of Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4BordeauxFrance
| | - Camille Genuer
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297BordeauxFrance
| | - Virginia Puente-Muñoz
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297BordeauxFrance
| | - Isabel Gauthereau
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297BordeauxFrance
| | - Eric Hosy
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297BordeauxFrance
| | | | - Gregory Giannone
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297BordeauxFrance
| | - Ingrid Chamma
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297BordeauxFrance
| | | | - Christel Poujol
- University of Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4BordeauxFrance
| | - Daniel Choquet
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297BordeauxFrance
| | - Matthieu Sainlos
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297BordeauxFrance
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11
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Anderson MC, Levy AD, Dharmasri PA, Metzbower SR, Blanpied TA. Trans-synaptic molecular context of NMDA receptor nanodomains. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.22.573055. [PMID: 38187545 PMCID: PMC10769418 DOI: 10.1101/2023.12.22.573055] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Tight coordination of the spatial relationships between protein complexes is required for cellular function. In neuronal synapses, many proteins responsible for neurotransmission organize into subsynaptic nanoclusters whose trans-cellular alignment modulates synaptic signal propagation. However, the spatial relationships between these proteins and NMDA receptors (NMDARs), which are required for learning and memory, remain undefined. Here, we mapped the relationship of key NMDAR subunits to reference proteins in the active zone and postsynaptic density using multiplexed super-resolution DNA-PAINT microscopy. GluN2A and GluN2B subunits formed nanoclusters with diverse configurations that, surprisingly, were not localized near presynaptic vesicle release sites marked by Munc13-1. However, a subset of presynaptic sites was configured to maintain NMDAR activation: these were internally denser, aligned with abundant PSD-95, and associated closely with specific NMDAR nanodomains. This work reveals a new principle regulating NMDAR signaling and suggests that synaptic functional architecture depends on assembly of multiprotein nanodomains whose interior construction is conditional on trans-cellular relationships.
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Affiliation(s)
- Michael C Anderson
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Aaron D Levy
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Poorna A Dharmasri
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA
- Current address: Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sarah R Metzbower
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- Current address: Nikon Instruments Inc, Melville, NY, USA
| | - Thomas A Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
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12
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Jo D, Arjunan A, Choi S, Jung YS, Park J, Jo J, Kim OY, Song J. Oligonol ameliorates liver function and brain function in the 5 × FAD mouse model: transcriptional and cellular analysis. Food Funct 2023; 14:9650-9670. [PMID: 37843873 DOI: 10.1039/d3fo03451h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
Alzheimer's disease (AD) is a common neurodegenerative disease worldwide and is accompanied by memory deficits, personality changes, anxiety, depression, and social difficulties. For treatment of AD, many researchers have attempted to find medicinal resources with high effectiveness and without side effects. Oligonol is a low molecular weight polypeptide derived from lychee fruit extract. We investigated the effects of oligonol in 5 × FAD transgenic AD mice, which developed severe amyloid pathology, through behavioral tests (Barnes maze, marble burying, and nestle shredding) and molecular experiments. Oligonol treatment attenuated blood glucose levels and increased the antioxidant response in the livers of 5 × FAD mice. Moreover, the behavioral score data showed improvements in anxiety, depressive behavior, and cognitive impairment following a 2-month course of orally administered oligonol. Oligonol treatment not only altered the circulating levels of cytokines and adipokines in 5 × FAD mice, but also significantly enhanced the mRNA and protein levels of antioxidant enzymes and synaptic plasticity in the brain cortex and hippocampus. Therefore, we highlight the therapeutic potential of oligonol to attenuate neuropsychiatric problems and improve memory deficits in the early stage of AD.
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Affiliation(s)
- Danbi Jo
- Department of Anatomy, Chonnam National University Medical School, Seoyangro 264, Hwasun 58128, Republic of Korea.
- Biomedical Science Graduate Program (BMSGP), Chonnam National University, Seoyangro 264, Hwasun 58128, Republic of Korea
| | - Archana Arjunan
- Department of Anatomy, Chonnam National University Medical School, Seoyangro 264, Hwasun 58128, Republic of Korea.
| | - Seoyoon Choi
- Department of Anatomy, Chonnam National University Medical School, Seoyangro 264, Hwasun 58128, Republic of Korea.
- Biomedical Science Graduate Program (BMSGP), Chonnam National University, Seoyangro 264, Hwasun 58128, Republic of Korea
| | - Yoon Seok Jung
- Department of Anatomy, Chonnam National University Medical School, Seoyangro 264, Hwasun 58128, Republic of Korea.
| | - Jihyun Park
- Department of Food Science and Nutrition, Dong-A University, Nakdong-daero 550 beon-gil, Saha-gu, Busan, 49315, Republic of Korea.
- Department of Health Sciences, Graduate School of Dong-A University, Nakdong-daero 550 beon-gil, Saha-gu, Busan, 49315, Republic of Korea
| | - Jihoon Jo
- Department of Biomedical Science, Chonnam National University Medical School, Seoyangro 264, Hwasun 58128, Republic of Korea.
| | - Oh Yoen Kim
- Department of Food Science and Nutrition, Dong-A University, Nakdong-daero 550 beon-gil, Saha-gu, Busan, 49315, Republic of Korea.
- Department of Health Sciences, Graduate School of Dong-A University, Nakdong-daero 550 beon-gil, Saha-gu, Busan, 49315, Republic of Korea
| | - Juhyun Song
- Department of Anatomy, Chonnam National University Medical School, Seoyangro 264, Hwasun 58128, Republic of Korea.
- Biomedical Science Graduate Program (BMSGP), Chonnam National University, Seoyangro 264, Hwasun 58128, Republic of Korea
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13
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Tanaka H, Funahashi J, Hirano T. Live-cell imaging of endocytosed synaptophysin around individual hippocampal presynaptic active zones. Front Cell Neurosci 2023; 17:1277729. [PMID: 37927445 PMCID: PMC10620501 DOI: 10.3389/fncel.2023.1277729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 10/06/2023] [Indexed: 11/07/2023] Open
Abstract
In presynaptic terminals 4 types of endocytosis, kiss-and-run, clathrin-mediated, bulk and ultrafast endocytosis have been reported to maintain repetitive exocytosis of neurotransmitter. However, detailed characteristics and relative contribution of each type of endocytosis still need to be determined. Our previous live-cell imaging study demonstrated individual exocytosis events of synaptic vesicle within an active-zone-like membrane (AZLM) formed on glass using synaptophysin tagged with a pH-sensitive fluorescent protein. On the other hand, individual endocytosis events of postsynaptic receptors were recorded with a rapid extracellular pH exchange method. Combining these methods, here we live-cell imaged endocytosed synaptophysin with total internal reflection fluorescence microscopy in rat hippocampal culture preparations. Clathrin-dependent and -independent endocytosis, which was seemingly bulk endocytosis, occurred within several seconds after electrical stimulation at multiple locations around AZLM at room temperature, with the locations varying trial to trial. The contribution of clathrin-independent endocytosis was more prominent when the number of stimulation pulses was large. The skewness of synaptophysin distribution in intracellular vesicles became smaller after addition of a clathrin inhibitor, which suggests that clathrin-dependent endocytosis concentrates synaptophysin. Ultrafast endocytosis was evident immediately after stimulation only at near physiological temperature and was the predominant endocytosis when the number of stimulation pulses was small.
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Affiliation(s)
- Hiromitsu Tanaka
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
- Department of Developmental Biology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Junichiro Funahashi
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Tomoo Hirano
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
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14
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Dharmasri PA, Levy AD, Blanpied TA. Differential nanoscale organization of excitatory synapses onto excitatory vs inhibitory neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.06.556279. [PMID: 37732271 PMCID: PMC10508768 DOI: 10.1101/2023.09.06.556279] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
A key feature of excitatory synapses is the existence of subsynaptic protein nanoclusters whose precise alignment across the cleft in a trans-synaptic nanocolumn influences the strength of synaptic transmission. However, whether nanocolumn properties vary between excitatory synapses functioning in different cellular contexts is unknown. We used a combination of confocal and DNA-PAINT super-resolution microscopy to directly compare the organization of shared scaffold proteins at two important excitatory synapses - those forming onto excitatory principal neurons (Ex→Ex synapses) and those forming onto parvalbumin-expressing interneurons (Ex→PV synapses). As in Ex→Ex synapses, we find that in Ex→PV synapses presynaptic Munc13-1 and postsynaptic PSD-95 both form nanoclusters that demonstrate alignment, underscoring synaptic nanostructure and the trans-synaptic nanocolumn as conserved organizational principles of excitatory synapses. Despite the general conservation of these features, we observed specific differences in the characteristics of pre- and postsynaptic Ex→PV nanostructure. Ex→PV synapses contained larger PSDs with fewer PSD-95 NCs when accounting for size than Ex→Ex synapses. Furthermore, the PSD-95 NCs were larger and denser. The identity of the postsynaptic cell also had a retrograde impact on Munc13-1 organization, as Ex→PV synapses hosted larger Munc13-1 puncta that contained less dense but larger and more numerous Munc13-1 NCs. Moreover, we measured the spatial variability of transsynaptic alignment in these synapse types, revealing protein alignment in Ex→PV synapses over a distinct range of distances compared to Ex→Ex synapses. We conclude that while general principles of nanostructure and alignment are shared, cell-specific elements of nanodomain organization likely contribute to functional diversity of excitatory synapses. Understanding the rules of synapse nanodomain assembly, which themselves are cell-type specific, will be essential for illuminating brain network dynamics.
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Affiliation(s)
- Poorna A Dharmasri
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland 21201
- University of Maryland Medicine Institute of Neuroscience Discovery, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Aaron D Levy
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
- University of Maryland Medicine Institute of Neuroscience Discovery, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Thomas A Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland 21201
- University of Maryland Medicine Institute of Neuroscience Discovery, University of Maryland School of Medicine, Baltimore, Maryland 21201
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15
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Broadhead MJ, Ayvazian-Hancock A, Doucet K, Kantelberg O, Motherwell L, Zhu F, Grant SGN, Horrocks MH, Miles GB. Synaptic expression of TAR-DNA-binding protein 43 in the mouse spinal cord determined using super-resolution microscopy. Front Mol Neurosci 2023; 16:1027898. [PMID: 37671010 PMCID: PMC10475998 DOI: 10.3389/fnmol.2023.1027898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 06/22/2023] [Indexed: 09/07/2023] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is characterised by a loss of motor neurons in the brain and spinal cord that is preceded by early-stage changes in synapses that may be associated with TAR-DNA-Binding Protein 43 (TDP-43) pathology. Cellular inclusions of hyperphosphorylated TDP-43 (pTDP-43) are a key hallmark of neurodegenerative diseases such ALS. However, there has been little characterisation of the synaptic expression of TDP-43 inside subpopulations of spinal cord synapses. This study utilises a range of high-resolution and super-resolution microscopy techniques with immunolabelling, as well as an aptamer-based TDP-43 labelling strategy visualised with single-molecule localisation microscopy, to characterise and quantify the presence of pTDP-43 in populations of excitatory synapses near where motor neurons reside in the lateral ventral horn of the mouse lumbar spinal cord. We observe that TDP-43 is expressed in approximately half of spinal cord synapses as nanoscale clusters. Synaptic TDP-43 clusters are found most abundantly at synapses associated with VGLUT1-positive presynaptic terminals, compared to VGLUT2-associated synapses. Our nanoscopy techniques showed no difference in the subsynaptic expression of pTDP-43 in the ALS mouse model, SOD1G93a, compared to healthy controls, despite prominent structural deficits in VGLUT1-associated synapses in SOD1G93a mice. This research characterises the basic synaptic expression of TDP-43 with nanoscale precision and provides a framework with which to investigate the potential relationship between TDP-43 pathology and synaptic pathology in neurodegenerative diseases.
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Affiliation(s)
- Matthew J. Broadhead
- School of Psychology and Neuroscience, University of St. Andrews, St. Andrews, United Kingdom
- Centre of Biophotonics, University of St. Andrews, St. Andrews, United Kingdom
- Edinburgh Super-Resolution Imaging Consortium, Heriot-Watt University, Edinburgh, United Kingdom
| | - Ani Ayvazian-Hancock
- School of Psychology and Neuroscience, University of St. Andrews, St. Andrews, United Kingdom
- Centre of Biophotonics, University of St. Andrews, St. Andrews, United Kingdom
| | - Katherine Doucet
- School of Psychology and Neuroscience, University of St. Andrews, St. Andrews, United Kingdom
- Centre of Biophotonics, University of St. Andrews, St. Andrews, United Kingdom
| | - Owen Kantelberg
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - Lesley Motherwell
- School of Psychology and Neuroscience, University of St. Andrews, St. Andrews, United Kingdom
- Centre of Biophotonics, University of St. Andrews, St. Andrews, United Kingdom
| | - Fei Zhu
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Seth G. N. Grant
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Simons Initiative for the Developing Brain (SIDB), Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Mathew H. Horrocks
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
- IRR Chemistry Hub, Institute for Regeneration and Repair, University of Edinburgh, Edinburgh, United Kingdom
| | - Gareth B. Miles
- School of Psychology and Neuroscience, University of St. Andrews, St. Andrews, United Kingdom
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16
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Bell MK, Lee CT, Rangamani P. Spatiotemporal modelling reveals geometric dependence of AMPAR dynamics on dendritic spine morphology. J Physiol 2023; 601:3329-3350. [PMID: 36326020 DOI: 10.1113/jp283407] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 11/01/2022] [Indexed: 08/02/2023] Open
Abstract
The modification of neural circuits depends on the strengthening and weakening of synaptic connections. Synaptic strength is often correlated to the density of the ionotropic, glutamatergic receptors, AMPARs, (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors) at the postsynaptic density (PSD). While AMPAR density is known to change based on complex biological signalling cascades, the effect of geometric factors such as dendritic spine shape, size and curvature remain poorly understood. In this work, we developed a deterministic, spatiotemporal model to study the dynamics of AMPARs during long-term potentiation (LTP). This model includes a minimal set of biochemical events that represent the upstream signalling events, trafficking of AMPARs to and from the PSD, lateral diffusion in the plane of the spine membrane, and the presence of an extrasynaptic AMPAR pool. Using idealized and realistic spine geometries, we show that the dynamics and increase of bound AMPARs at the PSD depends on a combination of endo- and exocytosis, membrane diffusion, the availability of free AMPARs and intracellular signalling interactions. We also found non-monotonic relationships between spine volume and the change in AMPARs at the PSD, suggesting that spines restrict changes in AMPARs to optimize resources and prevent runaway potentiation. KEY POINTS: Synaptic plasticity involves dynamic biochemical and physical remodelling of small protrusions called dendritic spines along the dendrites of neurons. Proper synaptic functionality within these spines requires changes in receptor number at the synapse, which has implications for downstream neural functions, such as learning and memory formation. In addition to being signalling subcompartments, spines also have unique morphological features that can play a role in regulating receptor dynamics on the synaptic surface. We have developed a spatiotemporal model that couples biochemical signalling and receptor trafficking modalities in idealized and realistic spine geometries to investigate the role of biochemical and biophysical factors in synaptic plasticity. Using this model, we highlight the importance of spine size and shape in regulating bound AMPA receptor dynamics that govern synaptic plasticity, and predict how spine shape might act to reset synaptic plasticity as a built-in resource optimization and regulation tool.
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Affiliation(s)
- Miriam K Bell
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, USA
| | - Christopher T Lee
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, USA
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, USA
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17
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Needs HI, Wilkinson KA, Henley JM, Collinson I. Aggregation-prone Tau impairs mitochondrial import, which affects organelle morphology and neuronal complexity. J Cell Sci 2023; 136:jcs260993. [PMID: 37303235 PMCID: PMC10357015 DOI: 10.1242/jcs.260993] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 06/05/2023] [Indexed: 06/13/2023] Open
Abstract
Mitochondrial protein import is essential for organellar biogenesis, and thereby for the sufficient supply of cytosolic ATP - which is particularly important for cells with high energy demands like neurons. This study explores the prospect of import machinery perturbation as a cause of neurodegeneration instigated by the accumulation of aggregating proteins linked to disease. We found that the aggregation-prone Tau variant (TauP301L) reduces the levels of components of the import machinery of the outer (TOM20, encoded by TOMM20) and inner membrane (TIM23, encoded by TIMM23) while associating with TOM40 (TOMM40). Intriguingly, this interaction affects mitochondrial morphology, but not protein import or respiratory function; raising the prospect of an intrinsic rescue mechanism. Indeed, TauP301L induced the formation of tunnelling nanotubes (TNTs), potentially for the recruitment of healthy mitochondria from neighbouring cells and/or the disposal of mitochondria incapacitated by aggregated Tau. Consistent with this, inhibition of TNT formation (and rescue) reveals Tau-induced import impairment. In primary neuronal cultures, TauP301L induced morphological changes characteristic of neurodegeneration. Interestingly, these effects were mirrored in cells where the import sites were blocked artificially. Our results reveal a link between aggregation-prone Tau and defective mitochondrial import relevant to disease.
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Affiliation(s)
- Hope I. Needs
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | | | - Jeremy M. Henley
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Ian Collinson
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
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18
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Dupuis JP, Nicole O, Groc L. NMDA receptor functions in health and disease: Old actor, new dimensions. Neuron 2023:S0896-6273(23)00344-6. [PMID: 37236178 DOI: 10.1016/j.neuron.2023.05.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 04/06/2023] [Accepted: 05/02/2023] [Indexed: 05/28/2023]
Abstract
N-Methyl-D-aspartate ionotropic glutamate receptors (NMDARs) play key roles in synaptogenesis, synaptic maturation, long-term plasticity, neuronal network activity, and cognition. Mirroring this wide range of instrumental functions, abnormalities in NMDAR-mediated signaling have been associated with numerous neurological and psychiatric disorders. Thus, identifying the molecular mechanisms underpinning the physiological and pathological contributions of NMDAR has been a major area of investigation. Over the past decades, a large body of literature has flourished, revealing that the physiology of ionotropic glutamate receptors cannot be restricted to fluxing ions, and involves additional facets controlling synaptic transmissions in health and disease. Here, we review newly discovered dimensions of postsynaptic NMDAR signaling supporting neural plasticity and cognition, such as the nanoscale organization of NMDAR complexes, their activity-dependent redistributions, and non-ionotropic signaling capacities. We also discuss how dysregulations of these processes may directly contribute to NMDAR-dysfunction-related brain diseases.
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Affiliation(s)
- Julien P Dupuis
- University of Bordeaux, CNRS, IINS, UMR 5297, 33000 Bordeaux, France
| | - Olivier Nicole
- University of Bordeaux, CNRS, IINS, UMR 5297, 33000 Bordeaux, France
| | - Laurent Groc
- University of Bordeaux, CNRS, IINS, UMR 5297, 33000 Bordeaux, France.
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19
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Leistner C, Wilkinson M, Burgess A, Lovatt M, Goodbody S, Xu Y, Deuchars S, Radford SE, Ranson NA, Frank RAW. The in-tissue molecular architecture of β-amyloid pathology in the mammalian brain. Nat Commun 2023; 14:2833. [PMID: 37198197 PMCID: PMC10192217 DOI: 10.1038/s41467-023-38495-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 05/04/2023] [Indexed: 05/19/2023] Open
Abstract
Amyloid plaques composed of Aβ fibrils are a hallmark of Alzheimer's disease (AD). However, the molecular architecture of amyloid plaques in the context of fresh mammalian brain tissue is unknown. Here, using cryogenic correlated light and electron tomography we report the in situ molecular architecture of Aβ fibrils in the AppNL-G-F familial AD mouse model containing the Arctic mutation and an atomic model of ex vivo purified Arctic Aβ fibrils. We show that in-tissue Aβ fibrils are arranged in a lattice or parallel bundles, and are interdigitated by subcellular compartments, extracellular vesicles, extracellular droplets and extracellular multilamellar bodies. The Arctic Aβ fibril differs significantly from an earlier AppNL-F fibril structure, indicating a striking effect of the Arctic mutation. These structural data also revealed an ensemble of additional fibrillar species, including thin protofilament-like rods and branched fibrils. Together, these results provide a structural model for the dense network architecture that characterises β-amyloid plaque pathology.
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Affiliation(s)
- Conny Leistner
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Martin Wilkinson
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Ailidh Burgess
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
- Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Megan Lovatt
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Stanley Goodbody
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Yong Xu
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
- AstraZeneca, 1 Francis Crick Avenue, Cambridge, CB2 0AA, UK
| | - Susan Deuchars
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
| | - Neil A Ranson
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
| | - René A W Frank
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
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20
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Xu B, Yin M, Yang Y, Zou Y, Liu W, Qiao L, Zhang J, Wang Z, Wu Y, Shen H, Sun M, Liu W, Xue W, Fan Y, Zhang Q, Chen B, Wu X, Shi Y, Lu F, Zhao Y, Xiao Z, Dai J. Transplantation of neural stem progenitor cells from different sources for severe spinal cord injury repair in rat. Bioact Mater 2023; 23:300-313. [DOI: 10.1016/j.bioactmat.2022.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 10/28/2022] [Accepted: 11/15/2022] [Indexed: 11/24/2022] Open
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21
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Jung JH, Chen X, Reese TS. Cryo-EM tomography and automatic segmentation delineate modular structures in the postsynaptic density. Front Synaptic Neurosci 2023; 15:1123564. [PMID: 37091879 PMCID: PMC10117989 DOI: 10.3389/fnsyn.2023.1123564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 03/02/2023] [Indexed: 04/08/2023] Open
Abstract
Postsynaptic densities (PSDs) are large protein complexes associated with the postsynaptic membrane of excitatory synapses important for synaptic function including plasticity. Conventional electron microscopy (EM) typically depicts PSDs as compact disk-like structures of hundreds of nanometers in size. Biochemically isolated PSDs were also similar in dimension revealing a predominance of proteins with the ability to polymerize into an extensive scaffold; several EM studies noted their irregular contours with often small granular structures (<30 nm) and holes. Super-resolution light microscopy studies observed clusters of PSD elements and their activity-induced lateral movement. Furthermore, our recent EM study on PSD fractions after sonication observed PSD fragments (40–90 nm in size) separate from intact PSDs; however, such structures within PSDs remained unidentified. Here we examined isolated PSDs by cryo-EM tomography with our new approach of automatic segmentation that enables delineation of substructures and their quantitative analysis. The delineated substructures broadly varied in size, falling behind 30 nm or exceeding 100 nm and showed that a considerable portion of the substructures (>38%) in isolated PSDs was in the same size range as those fragments. Furthermore, substructures spanning the entire thickness of the PSD were found, large enough to contain both membrane-associated and cytoplasmic proteins of the PSD; interestingly, they were similar to nanodomains in frequency. The structures detected here appear to constitute the isolated PSD as modules of various compositions, and this modular nature may facilitate remodeling of the PSD for proper synaptic function and plasticity.
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22
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Griffiths J, Grant SGN. Synapse pathology in Alzheimer's disease. Semin Cell Dev Biol 2023; 139:13-23. [PMID: 35690535 DOI: 10.1016/j.semcdb.2022.05.028] [Citation(s) in RCA: 26] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 05/12/2022] [Accepted: 05/27/2022] [Indexed: 12/31/2022]
Abstract
Synapse loss and damage are central features of Alzheimer's disease (AD) and contribute to the onset and progression of its behavioural and physiological features. Here we review the literature describing synapse pathology in AD, from what we have learned from microscopy in terms of its impacts on synapse architecture, to the mechanistic role of Aβ, tau and glial cells, mitochondrial dysfunction, and the link with AD risk genes. We consider the emerging view that synapse pathology may operate at a further level, that of synapse diversity, and discuss the prospects for leveraging new synaptome mapping methods to comprehensively understand the molecular properties of vulnerable and resilient synapses. Uncovering AD impacts on brain synapse diversity should inform therapeutic approaches targeted at preserving or replenishing lost and damaged synapses and aid the interpretation of clinical imaging approaches that aim to measure synapse damage.
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Affiliation(s)
- Jessica Griffiths
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK; Dementia Research Institute at Imperial College, Department of Brain Sciences, Imperial College London, London W12 0NN, UK
| | - Seth G N Grant
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK.
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23
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Hindley N, Sanchez Avila A, Henstridge C. Bringing synapses into focus: Recent advances in synaptic imaging and mass-spectrometry for studying synaptopathy. Front Synaptic Neurosci 2023; 15:1130198. [PMID: 37008679 PMCID: PMC10050382 DOI: 10.3389/fnsyn.2023.1130198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 02/28/2023] [Indexed: 03/17/2023] Open
Abstract
Synapses are integral for healthy brain function and are becoming increasingly recognized as key structures in the early stages of brain disease. Understanding the pathological processes driving synaptic dysfunction will unlock new therapeutic opportunities for some of the most devastating diseases of our time. To achieve this we need a solid repertoire of imaging and molecular tools to interrogate synaptic biology at greater resolution. Synapses have historically been examined in small numbers, using highly technical imaging modalities, or in bulk, using crude molecular approaches. However, recent advances in imaging techniques are allowing us to analyze large numbers of synapses, at single-synapse resolution. Furthermore, multiplexing is now achievable with some of these approaches, meaning we can examine multiple proteins at individual synapses in intact tissue. New molecular techniques now allow accurate quantification of proteins from isolated synapses. The development of increasingly sensitive mass-spectrometry equipment means we can now scan the synaptic molecular landscape almost in totality and see how this changes in disease. As we embrace these new technical developments, synapses will be viewed with clearer focus, and the field of synaptopathy will become richer with insightful and high-quality data. Here, we will discuss some of the ways in which synaptic interrogation is being facilitated by methodological advances, focusing on imaging, and mass spectrometry.
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Affiliation(s)
- Nicole Hindley
- Division of Cellular and Systems Medicine, University of Dundee, Dundee, United Kingdom
- *Correspondence: Nicole Hindley,
| | - Anna Sanchez Avila
- Division of Cellular and Systems Medicine, University of Dundee, Dundee, United Kingdom
- Euan Macdonald Centre for Motor Neuron Disease, University of Edinburgh, Edinburgh, United Kingdom
| | - Christopher Henstridge
- Division of Cellular and Systems Medicine, University of Dundee, Dundee, United Kingdom
- Euan Macdonald Centre for Motor Neuron Disease, University of Edinburgh, Edinburgh, United Kingdom
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24
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Droogers WJ, MacGillavry HD. Plasticity of postsynaptic nanostructure. Mol Cell Neurosci 2023; 124:103819. [PMID: 36720293 DOI: 10.1016/j.mcn.2023.103819] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 01/19/2023] [Accepted: 01/23/2023] [Indexed: 01/31/2023] Open
Abstract
The postsynaptic density (PSD) of excitatory synapses is built from a wide variety of scaffolding proteins, receptors, and signaling molecules that collectively orchestrate synaptic transmission. Seminal work over the past decades has led to the identification and functional characterization of many PSD components. In contrast, we know far less about how these constituents are assembled within synapses, and how this organization contributes to synapse function. Notably, recent evidence from high-resolution microscopy studies and in silico models, highlights the importance of the precise subsynaptic structure of the PSD for controlling the strength of synaptic transmission. Even further, activity-driven changes in the distribution of glutamate receptors are acknowledged to contribute to long-term changes in synaptic efficacy. Thus, defining the mechanisms that drive structural changes within the PSD are important for a molecular understanding of synaptic transmission and plasticity. Here, we review the current literature on how the PSD is organized to mediate basal synaptic transmission and how synaptic activity alters the nanoscale organization of synapses to sustain changes in synaptic strength.
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Affiliation(s)
- W J Droogers
- Division of Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH, The Netherlands
| | - H D MacGillavry
- Division of Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH, The Netherlands.
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25
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de Moliner F, Konieczna Z, Mendive-Tapia L, Saleeb RS, Morris K, Gonzalez-Vera JA, Kaizuka T, Grant SGN, Horrocks MH, Vendrell M. Small Fluorogenic Amino Acids for Peptide-Guided Background-Free Imaging. Angew Chem Int Ed Engl 2023; 62:e202216231. [PMID: 36412996 PMCID: PMC10108274 DOI: 10.1002/anie.202216231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 11/23/2022]
Abstract
The multiple applications of super-resolution microscopy have prompted the need for minimally invasive labeling strategies for peptide-guided fluorescence imaging. Many fluorescent reporters display limitations (e.g., large and charged scaffolds, non-specific binding) as building blocks for the construction of fluorogenic peptides. Herein we have built a library of benzodiazole amino acids and systematically examined them as reporters for background-free fluorescence microscopy. We have identified amine-derivatized benzoselenadiazoles as scalable and photostable amino acids for the straightforward solid-phase synthesis of fluorescent peptides. Benzodiazole amino acids retain the binding capabilities of bioactive peptides and display excellent signal-to-background ratios. Furthermore, we have demonstrated their application in peptide-PAINT imaging of postsynaptic density protein-95 nanoclusters in the synaptosomes from mouse brain tissues.
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Affiliation(s)
- Fabio de Moliner
- Centre for Inflammation Research, The University of Edinburgh, UK
| | | | | | | | - Katie Morris
- EaStCHEM School of Chemistry, The University of Edinburgh, UK
| | | | - Takeshi Kaizuka
- Centre for Clinical Brain Sciences, The University of Edinburgh, UK
| | - Seth G N Grant
- Centre for Clinical Brain Sciences, The University of Edinburgh, UK
| | | | - Marc Vendrell
- Centre for Inflammation Research, The University of Edinburgh, UK
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26
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de Moliner F, Konieczna Z, Mendive‐Tapia L, Saleeb RS, Morris K, Gonzalez‐Vera JA, Kaizuka T, Grant SGN, Horrocks MH, Vendrell M. Small Fluorogenic Amino Acids for Peptide-Guided Background-Free Imaging. ANGEWANDTE CHEMIE (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 135:e202216231. [PMID: 38515539 PMCID: PMC10952862 DOI: 10.1002/ange.202216231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Indexed: 11/23/2022]
Abstract
The multiple applications of super-resolution microscopy have prompted the need for minimally invasive labeling strategies for peptide-guided fluorescence imaging. Many fluorescent reporters display limitations (e.g., large and charged scaffolds, non-specific binding) as building blocks for the construction of fluorogenic peptides. Herein we have built a library of benzodiazole amino acids and systematically examined them as reporters for background-free fluorescence microscopy. We have identified amine-derivatized benzoselenadiazoles as scalable and photostable amino acids for the straightforward solid-phase synthesis of fluorescent peptides. Benzodiazole amino acids retain the binding capabilities of bioactive peptides and display excellent signal-to-background ratios. Furthermore, we have demonstrated their application in peptide-PAINT imaging of postsynaptic density protein-95 nanoclusters in the synaptosomes from mouse brain tissues.
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Affiliation(s)
| | | | | | | | - Katie Morris
- EaStCHEM School of ChemistryThe University of EdinburghUK
| | | | - Takeshi Kaizuka
- Centre for Clinical Brain SciencesThe University of EdinburghUK
| | | | | | - Marc Vendrell
- Centre for Inflammation ResearchThe University of EdinburghUK
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27
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Mougios N, Opazo F, Rizzoli SO, Reshetniak S. Trafficking proteins show limited differences in mobility across different postsynaptic spines. iScience 2023; 26:105971. [PMID: 36718370 PMCID: PMC9883188 DOI: 10.1016/j.isci.2023.105971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/24/2022] [Accepted: 01/10/2023] [Indexed: 01/14/2023] Open
Abstract
The function of the postsynaptic compartment is based on the presence and activity of postsynaptic receptors, whose dynamics are controlled by numerous scaffolding, signaling and trafficking proteins. Although the receptors and the scaffolding proteins have received substantial attention, the trafficking proteins have not been investigated extensively. Their mobility rates are unknown, and it is unclear how the postsynaptic environment affects their dynamics. To address this, we analyzed several trafficking proteins (α-synuclein, amphiphysin, calmodulin, doc2a, dynamin, and endophilin), estimating their movement rates in the dendritic shaft, as well as in morphologically distinct "mushroom" and "stubby" postsynapse types. The diffusion parameters were surprisingly similar across dendritic compartments, and a few differences between proteins became evident only in the presence of a synapse neck. We conclude that the movement of trafficking proteins is not strongly affected by the postsynaptic compartment, in stark contrast to the presynapse, which regulates strongly the movement of such proteins.
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Affiliation(s)
- Nikolaos Mougios
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany,Center for Biostructural Imaging of Neurodegeneration (BIN), University of Göttingen Medical Center, 37075 Göttingen, Germany
| | - Felipe Opazo
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany,Center for Biostructural Imaging of Neurodegeneration (BIN), University of Göttingen Medical Center, 37075 Göttingen, Germany,NanoTag Biotechnologies GmbH, Göttingen, Germany
| | - Silvio O. Rizzoli
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany,Center for Biostructural Imaging of Neurodegeneration (BIN), University of Göttingen Medical Center, 37075 Göttingen, Germany,Corresponding author
| | - Sofiia Reshetniak
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany,Corresponding author
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28
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Bell MK, Rangamani P. Crosstalk between biochemical signalling network architecture and trafficking governs AMPAR dynamics in synaptic plasticity. J Physiol 2023. [PMID: 36620889 DOI: 10.1113/jp284029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 01/03/2023] [Indexed: 01/10/2023] Open
Abstract
Synaptic plasticity involves modification of both biochemical and structural components of neurons. Many studies have revealed that the change in the number density of the glutamatergic receptor AMPAR at the synapse is proportional to synaptic weight update; an increase in AMPAR corresponds to strengthening of synapses while a decrease in AMPAR density weakens synaptic connections. The dynamics of AMPAR are thought to be regulated by upstream signalling, primarily the calcium-CaMKII pathway, trafficking to and from the synapse, and influx from extrasynaptic sources. Previous work in the field of deterministic modelling of CaMKII dynamics has assumed bistable kinetics, while experiments and rule-based modelling have revealed that CaMKII dynamics can be either monostable or ultrasensitive. This raises the following question: how does the choice of model assumptions involving CaMKII dynamics influence AMPAR dynamics at the synapse? To answer this question, we have developed a set of models using compartmental ordinary differential equations to systematically investigate contributions of different signalling and trafficking variations, along with their coupled effects, on AMPAR dynamics at the synaptic site. We find that the properties of the model including network architecture describing different stability features of CaMKII and parameters that capture the endocytosis and exocytosis of AMPAR significantly affect the integration of fast upstream species by slower downstream species. Furthermore, we predict that the model outcome, as determined by bound AMPAR at the synaptic site, depends on (1) the choice of signalling model (bistable CaMKII or monostable CaMKII dynamics), (2) trafficking versus influx contributions and (3) frequency of stimulus. KEY POINTS: The density of AMPA receptors (AMPARs) at the postsynaptic density of the synapse provides a readout of synaptic plasticity, which involves crosstalk between complex biochemical signalling networks including CaMKII dynamics and trafficking pathways including exocytosis and endocytosis. Here we build a model that integrates CaMKII dynamics and AMPAR trafficking to explore this crosstalk. We compare different models of CaMKII that result in monostable or bistable kinetics and their impact on AMPAR dynamics. Our results show that AMPAR density depends on the coupling between aspects of biochemical signalling and trafficking. Specifically, assumptions regarding CaMKII dynamics and its stability features can alter AMPAR density at the synapse. Our model also predicts that the kinetics of trafficking versus influx of AMPAR from the extrasynaptic space can further impact AMPAR density. Thus, the contributions of both signalling and trafficking should be considered in computational models.
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Affiliation(s)
- Miriam K Bell
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, USA
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, USA
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29
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Bulovaite E, Qiu Z, Kratschke M, Zgraj A, Fricker DG, Tuck EJ, Gokhale R, Koniaris B, Jami SA, Merino-Serrais P, Husi E, Mendive-Tapia L, Vendrell M, O'Dell TJ, DeFelipe J, Komiyama NH, Holtmaat A, Fransén E, Grant SGN. A brain atlas of synapse protein lifetime across the mouse lifespan. Neuron 2022; 110:4057-4073.e8. [PMID: 36202095 PMCID: PMC9789179 DOI: 10.1016/j.neuron.2022.09.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 07/01/2022] [Accepted: 09/07/2022] [Indexed: 11/12/2022]
Abstract
The lifetime of proteins in synapses is important for their signaling, maintenance, and remodeling, and for memory duration. We quantified the lifetime of endogenous PSD95, an abundant postsynaptic protein in excitatory synapses, at single-synapse resolution across the mouse brain and lifespan, generating the Protein Lifetime Synaptome Atlas. Excitatory synapses have a wide range of PSD95 lifetimes extending from hours to several months, with distinct spatial distributions in dendrites, neurons, and brain regions. Synapses with short protein lifetimes are enriched in young animals and in brain regions controlling innate behaviors, whereas synapses with long protein lifetimes accumulate during development, are enriched in the cortex and CA1 where memories are stored, and are preferentially preserved in old age. Synapse protein lifetime increases throughout the brain in a mouse model of autism and schizophrenia. Protein lifetime adds a further layer to synapse diversity and enriches prevailing concepts in brain development, aging, and disease.
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Affiliation(s)
- Edita Bulovaite
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Zhen Qiu
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Maximilian Kratschke
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Adrianna Zgraj
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - David G Fricker
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Eleanor J Tuck
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Ragini Gokhale
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Babis Koniaris
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK; School of Computing, Edinburgh Napier University, Edinburgh EH10 5DT, UK
| | - Shekib A Jami
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Paula Merino-Serrais
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, UPM, 28223 Madrid, Spain; Instituto Cajal, CSIC, 28002 Madrid, Spain
| | - Elodie Husi
- Department of Basic Neurosciences, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland
| | - Lorena Mendive-Tapia
- Centre for Inflammation Research, University of Edinburgh, Edinburgh EH16 4TJ, UK
| | - Marc Vendrell
- Centre for Inflammation Research, University of Edinburgh, Edinburgh EH16 4TJ, UK
| | - Thomas J O'Dell
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Javier DeFelipe
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, UPM, 28223 Madrid, Spain; Instituto Cajal, CSIC, 28002 Madrid, Spain
| | - Noboru H Komiyama
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK; Simons Initiative for the Developing Brain (SIDB), Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, UK; The Patrick Wild Centre for Research into Autism, Fragile X Syndrome & Intellectual Disabilities, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, UK; Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Anthony Holtmaat
- Department of Basic Neurosciences, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland
| | - Erik Fransén
- Department of Computational Science and Technology, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, 10044 Stockholm, Sweden; Science for Life Laboratory, KTH Royal Institute of Technology, 171 65 Solna, Sweden
| | - Seth G N Grant
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK; Simons Initiative for the Developing Brain (SIDB), Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, UK.
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30
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Plaza-Diaz J, Radar AM, Baig AT, Leyba MF, Costabel MM, Zavala-Crichton JP, Sanchez-Martinez J, MacKenzie AE, Solis-Urra P. Physical Activity, Gut Microbiota, and Genetic Background for Children and Adolescents with Autism Spectrum Disorder. CHILDREN (BASEL, SWITZERLAND) 2022; 9:1834. [PMID: 36553278 PMCID: PMC9777368 DOI: 10.3390/children9121834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/19/2022] [Accepted: 11/24/2022] [Indexed: 11/29/2022]
Abstract
It is estimated that one in 100 children worldwide has been diagnosed with autism spectrum disorder (ASD). Children with ASD frequently suffer from gut dysbiosis and gastrointestinal issues, findings which possibly play a role in the pathogenesis and/or severity of their condition. Physical activity may have a positive effect on the composition of the intestinal microbiota of healthy adults. However, the effect of exercise both on the gastrointestinal problems and intestinal microbiota (and thus possibly on ASD) itself in affected children is unknown. In terms of understanding the physiopathology and manifestations of ASD, analysis of the gut-brain axis holds some promise. Here, we discuss the physiopathology of ASD in terms of genetics and microbiota composition, and how physical activity may be a promising non-pharmaceutical approach to improve ASD-related symptoms.
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Affiliation(s)
- Julio Plaza-Diaz
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, 18071 Granada, Spain
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON K1H 8L1, Canada
- Instituto de Investigación Biosanitaria IBS.GRANADA, Complejo Hospitalario Universitario de Granada, 18014 Granada, Spain
| | - Ana Mei Radar
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON K1H 8L1, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Aiman Tariq Baig
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON K1H 8L1, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Marcos Federico Leyba
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON K1H 8L1, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Maria Macarena Costabel
- Children’s Hospital of Eastern Ontario, Division of Urology, Department of Surgery, University of Ottawa, Ottawa, ON K1H 8L6, Canada
| | | | - Javier Sanchez-Martinez
- Escuela de Kinesiología, Facultad de Salud, Universidad Santo Tomás, Viña del Mar 2520298, Chile
| | - Alex E. MacKenzie
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON K1H 8L1, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Patricio Solis-Urra
- Faculty of Education and Social Sciences, Universidad Andres Bello, Viña del Mar 2531015, Chile
- PROFITH “PROmoting FITness and Health through Physical Activity” Research Group, Sport and Health University Research Institute (iMUDS), Department of Physical Education and Sports, Faculty of Sport Sciences, University of Granada, 18071 Granada, Spain
- Servicio de Medicina Nuclear, Hospital Universitario Virgen de las Nieves, 18014 Granada, Spain
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31
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Tomas-Roca L, Qiu Z, Fransén E, Gokhale R, Bulovaite E, Price DJ, Komiyama NH, Grant SGN. Developmental disruption and restoration of brain synaptome architecture in the murine Pax6 neurodevelopmental disease model. Nat Commun 2022; 13:6836. [PMID: 36369219 PMCID: PMC9652404 DOI: 10.1038/s41467-022-34131-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 10/14/2022] [Indexed: 11/13/2022] Open
Abstract
Neurodevelopmental disorders of genetic origin delay the acquisition of normal abilities and cause disabling phenotypes. Nevertheless, spontaneous attenuation and even complete amelioration of symptoms in early childhood and adolescence can occur in many disorders, suggesting that brain circuits possess an intrinsic capacity to overcome the deficits arising from some germline mutations. We examined the molecular composition of almost a trillion excitatory synapses on a brain-wide scale between birth and adulthood in mice carrying a mutation in the homeobox transcription factor Pax6, a neurodevelopmental disorder model. Pax6 haploinsufficiency had no impact on total synapse number at any age. By contrast, the molecular composition of excitatory synapses, the postnatal expansion of synapse diversity and the acquisition of normal synaptome architecture were delayed in all brain regions, interfering with networks and electrophysiological simulations of cognitive functions. Specific excitatory synapse types and subtypes were affected in two key developmental age-windows. These phenotypes were reversed within 2-3 weeks of onset, restoring synapse diversity and synaptome architecture to the normal developmental trajectory. Synapse subtypes with rapid protein turnover mediated the synaptome remodeling. This brain-wide capacity for remodeling of synapse molecular composition to recover and maintain the developmental trajectory of synaptome architecture may help confer resilience to neurodevelopmental genetic disorders.
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Affiliation(s)
- Laura Tomas-Roca
- grid.4305.20000 0004 1936 7988Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB UK
| | - Zhen Qiu
- grid.4305.20000 0004 1936 7988Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB UK
| | - Erik Fransén
- grid.5037.10000000121581746Science for Life Laboratory, KTH Royal Institute of Technology, SE-171 65 Solna, Sweden
| | - Ragini Gokhale
- grid.4305.20000 0004 1936 7988Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB UK
| | - Edita Bulovaite
- grid.4305.20000 0004 1936 7988Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB UK
| | - David J. Price
- grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain (SIDB), Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Noboru H. Komiyama
- grid.4305.20000 0004 1936 7988Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain (SIDB), Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Seth G. N. Grant
- grid.4305.20000 0004 1936 7988Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain (SIDB), Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK
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32
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Lovatt M, Leistner C, Frank RAW. Bridging length scales from molecules to the whole organism by cryoCLEM and cryoET. Faraday Discuss 2022; 240:114-126. [PMID: 35959706 PMCID: PMC9642002 DOI: 10.1039/d2fd00081d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Resolving atomic structures of isolated proteins has uncovered mechanisms and fundamental processes in biology. However, many functions can only be tested in the context of intact cells and tissues that are many orders of magnitude larger than the macromolecules on which they depend. Therefore, methods that interrogate macromolecular structure in situ provide a means of directly relating structure to function across length scales. Here, we developed several workflows using cryogenic correlated light and electron microscopy (cryoCLEM) and electron tomography (cryoET) that can bridge this gap to reveal the molecular infrastructure that underlies higher order functions within cells and tissues. We also describe experimental design considerations, including cryoCLEM labelling, sample preparation, and quality control, for determining the in situ molecular architectures within native, hydrated cells and tissues.
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Affiliation(s)
- Megan Lovatt
- Astbury Centre of Structural Molecular Biology, School of Biomedical Sciences, Faculty of Biological Sciences, University of LeedsLS2 9JTUK
| | - Conny Leistner
- Astbury Centre of Structural Molecular Biology, School of Biomedical Sciences, Faculty of Biological Sciences, University of LeedsLS2 9JTUK
| | - René A. W. Frank
- Astbury Centre of Structural Molecular Biology, School of Biomedical Sciences, Faculty of Biological Sciences, University of LeedsLS2 9JTUK
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33
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O'Dell DE, Smith-Bell CA, Enquist LW, Engel EA, Schreurs BG. Eyeblink tract tracing with two strains of herpes simplex virus 1. Brain Res 2022; 1793:148040. [PMID: 35932812 DOI: 10.1016/j.brainres.2022.148040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 07/20/2022] [Accepted: 08/01/2022] [Indexed: 11/18/2022]
Abstract
BACKGROUND Neuroinvasive herpes simplex-1 (HSV-1) isolates including H129 and McIntyre cross at or near synapses labeling higher-order neurons directly connected to infected cells. H129 spreads predominately in the anterograde direction while McIntyre strains spread only in the retrograde direction. However, it is unknown if neurons are functional once infected with derivatives of H129 or McIntyre. NEW METHOD We describe a previously unpublished HSV-1 recombinant derived from H129 (HSV-373) expressing mCherry fluorescent reporters and one new McIntyre recombinant (HSV-780) expressing the mCherry fluorophore and demonstrate how infections affect neuron viability. RESULTS AND COMPARISON WITH EXISTING METHODS Each recombinant virus behaved similarly and spread to the target 4 days post-infection. We tested H129 recombinant infected neurons for neurodegeneration using Fluoro-jade C and found them to be necrotic as a result of viral infection. We performed dual inoculations with both HSV-772 and HSV-780 to identify cells comprising both the anterograde pathway and the retrograde pathway, respectively, of our circuit of study. We examined the presence of postsynaptic marker PSD-95, which plays a role in synaptic plasticity, in HSV-772 infected and in dual-infected rats (HSV-772 and HSV-780). PSD-95 reactivity decreased in HSV-772-infected neurons and dual-infected tissue had no PSD-95 reactivity. CONCLUSIONS Infection by these new recombinant viruses traced the circuit of interest but functional studies of the cells comprising the pathway were not possible because viral-infected neurons died as a result of necrosis or were stripped of PSD-95 by the time the viral labels reached the target.
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Affiliation(s)
- Deidre E O'Dell
- Department of Neuroscience, Rockefeller Neuroscience Institute, United States; West Virginia University, Morgantown, WV 26505, United States.
| | - Carrie A Smith-Bell
- Department of Neuroscience, Rockefeller Neuroscience Institute, United States; West Virginia University, Morgantown, WV 26505, United States
| | - Lynn W Enquist
- Department of Molecular Biology, United States; Princeton Neuroscience Institute, United States; Princeton University, Princeton, NJ 08544, United States
| | - Esteban A Engel
- Princeton Neuroscience Institute, United States; Princeton University, Princeton, NJ 08544, United States
| | - Bernard G Schreurs
- Department of Neuroscience, Rockefeller Neuroscience Institute, United States; West Virginia University, Morgantown, WV 26505, United States.
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Chen X, Crosby KC, Feng A, Purkey AM, Aronova MA, Winters CA, Crocker VT, Leapman RD, Reese TS, Dell’Acqua ML. Palmitoylation of A-kinase anchoring protein 79/150 modulates its nanoscale organization, trafficking, and mobility in postsynaptic spines. Front Synaptic Neurosci 2022; 14:1004154. [PMID: 36186623 PMCID: PMC9521714 DOI: 10.3389/fnsyn.2022.1004154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 08/23/2022] [Indexed: 11/29/2022] Open
Abstract
A-kinase anchoring protein 79-human/150-rodent (AKAP79/150) organizes signaling proteins to control synaptic plasticity. AKAP79/150 associates with the plasma membrane and endosomes through its N-terminal domain that contains three polybasic regions and two Cys residues that are reversibly palmitoylated. Mutations abolishing palmitoylation (AKAP79/150 CS) reduce its endosomal localization and association with the postsynaptic density (PSD). Here we combined advanced light and electron microscopy (EM) to characterize the effects of AKAP79/150 palmitoylation on its postsynaptic nanoscale organization, trafficking, and mobility in hippocampal neurons. Immunogold EM revealed prominent extrasynaptic membrane AKAP150 labeling with less labeling at the PSD. The label was at greater distances from the spine membrane for AKAP150 CS than WT in the PSD but not in extra-synaptic locations. Immunogold EM of GFP-tagged AKAP79 WT showed that AKAP79 adopts a vertical, extended conformation at the PSD with its N-terminus at the membrane, in contrast to extrasynaptic locations where it adopts a compact or open configurations of its N- and C-termini with parallel orientation to the membrane. In contrast, GFP-tagged AKAP79 CS was displaced from the PSD coincident with disruption of its vertical orientation, while proximity and orientation with respect to the extra-synaptic membrane was less impacted. Single-molecule localization microscopy (SMLM) revealed a heterogeneous distribution of AKAP150 with distinct high-density, nano-scale regions (HDRs) overlapping the PSD but more prominently located in the extrasynaptic membrane for WT and the CS mutant. Thick section scanning transmission electron microscopy (STEM) tomography revealed AKAP150 immunogold clusters similar in size to HDRs seen by SMLM and more AKAP150 labeled endosomes in spines for WT than for CS, consistent with the requirement for AKAP palmitoylation in endosomal trafficking. Hidden Markov modeling of single molecule tracking data revealed a bound/immobile fraction and two mobile fractions for AKAP79 in spines, with the CS mutant having shorter dwell times and faster transition rates between states than WT, suggesting that palmitoylation stabilizes individual AKAP molecules in various spine subpopulations. These data demonstrate that palmitoylation fine tunes the nanoscale localization, mobility, and trafficking of AKAP79/150 in dendritic spines, which might have profound effects on its regulation of synaptic plasticity.
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Affiliation(s)
- Xiaobing Chen
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, United States
- *Correspondence: Xiaobing Chen,
| | - Kevin C. Crosby
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, United States
| | - Austin Feng
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Alicia M. Purkey
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, United States
| | - Maria A. Aronova
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Christine A. Winters
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Virginia T. Crocker
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Richard D. Leapman
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Thomas S. Reese
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Mark L. Dell’Acqua
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, United States
- Mark L. Dell’Acqua,
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Seillier C, Lesept F, Toutirais O, Potzeha F, Blanc M, Vivien D. Targeting NMDA Receptors at the Neurovascular Unit: Past and Future Treatments for Central Nervous System Diseases. Int J Mol Sci 2022; 23:ijms231810336. [PMID: 36142247 PMCID: PMC9499580 DOI: 10.3390/ijms231810336] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 08/30/2022] [Accepted: 09/02/2022] [Indexed: 11/16/2022] Open
Abstract
The excitatory neurotransmission of the central nervous system (CNS) mainly involves glutamate and its receptors, especially N-methyl-D-Aspartate receptors (NMDARs). These receptors have been extensively described on neurons and, more recently, also on other cell types. Nowadays, the study of their differential expression and function is taking a growing place in preclinical and clinical research. The diversity of NMDAR subtypes and their signaling pathways give rise to pleiotropic functions such as brain development, neuronal plasticity, maturation along with excitotoxicity, blood-brain barrier integrity, and inflammation. NMDARs have thus emerged as key targets for the treatment of neurological disorders. By their large extracellular regions and complex intracellular structures, NMDARs are modulated by a variety of endogenous and pharmacological compounds. Here, we will present an overview of NMDAR functions on neurons and other important cell types involved in the pathophysiology of neurodegenerative, neurovascular, mental, autoimmune, and neurodevelopmental diseases. We will then discuss past and future development of NMDAR targeting drugs, including innovative and promising new approaches.
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Affiliation(s)
- Célia Seillier
- Normandie University, UNICAEN, INSERM, GIP Cyceron, Institute Blood and Brain @Caen-Normandie (BB@C), UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), 14000 Caen, France
| | - Flavie Lesept
- Lys Therapeutics, Cyceron, Boulevard Henri Becquerel, 14000 Caen, France
| | - Olivier Toutirais
- Normandie University, UNICAEN, INSERM, GIP Cyceron, Institute Blood and Brain @Caen-Normandie (BB@C), UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), 14000 Caen, France
- Department of Immunology and Histocompatibility (HLA), Caen University Hospital, CHU, 14000 Caen, France
| | - Fanny Potzeha
- Lys Therapeutics, Cyceron, Boulevard Henri Becquerel, 14000 Caen, France
| | - Manuel Blanc
- Lys Therapeutics, Cyceron, Boulevard Henri Becquerel, 14000 Caen, France
| | - Denis Vivien
- Normandie University, UNICAEN, INSERM, GIP Cyceron, Institute Blood and Brain @Caen-Normandie (BB@C), UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), 14000 Caen, France
- Department of Clinical Research, Caen University Hospital, CHU, 14000 Caen, France
- Correspondence:
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Chen X, Kuner T, Blanpied TA. Editorial: Quantifying and controlling the nano-architecture of neuronal synapses. Front Synaptic Neurosci 2022; 14:1024073. [PMID: 36160915 PMCID: PMC9491271 DOI: 10.3389/fnsyn.2022.1024073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Accepted: 08/24/2022] [Indexed: 11/13/2022] Open
Affiliation(s)
- Xiaobing Chen
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, United States
- *Correspondence: Xiaobing Chen
| | - Thomas Kuner
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
- Thomas Kuner
| | - Thomas A. Blanpied
- School of Medicine, University of Maryland, Baltimore, MD, United States
- Thomas A. Blanpied
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Willig KI. In vivo super-resolution of the brain – How to visualize the hidden nanoplasticity? iScience 2022; 25:104961. [PMID: 36093060 PMCID: PMC9449647 DOI: 10.1016/j.isci.2022.104961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Super-resolution fluorescence microscopy has entered most biological laboratories worldwide and its benefit is undisputable. Its application to brain imaging, for example in living mice, enables the study of sub-cellular structural plasticity and brain function directly in a living mammal. The demands of brain imaging on the different super-resolution microscopy techniques (STED, RESOLFT, SIM, ISM) and labeling strategies are discussed here as well as the challenges of the required cranial window preparation. Applications of super-resolution in the anesthetized mouse brain enlighten the stability and plasticity of synaptic nanostructures. These studies show the potential of in vivo super-resolution imaging and justify its application more widely in vivo to investigate the role of nanostructures in memory and learning.
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Nozawa K, Sogabe T, Hayashi A, Motohashi J, Miura E, Arai I, Yuzaki M. In vivo nanoscopic landscape of neurexin ligands underlying anterograde synapse specification. Neuron 2022; 110:3168-3185.e8. [PMID: 36007521 DOI: 10.1016/j.neuron.2022.07.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 05/04/2022] [Accepted: 07/27/2022] [Indexed: 11/17/2022]
Abstract
Excitatory synapses are formed and matured by the cooperative actions of synaptic organizers, such as neurexins (Nrxns), neuroligins (Nlgns), LRRTMs, and Cbln1. Recent super-resolution nanoscopy developments have revealed that many synaptic organizers, as well as glutamate receptors and glutamate release machinery, exist as nanoclusters within synapses. However, it is unclear how such nanodomains interact with each other to organize excitatory synapses in vivo. By applying X10 expansion microscopy to epitope tag knockin mice, we found that Cbln1, Nlgn1, and LRRTM1, which share Nrxn as a common presynaptic receptor, form overlapping or separate nanodomains depending on Nrxn with or without a sequence encoded by splice site 4. The size and position of glutamate receptor nanodomains of GluD1, NMDA, and AMPA receptors were regulated by Cbln1, Nlgn1, and LRRTM1 nanodomains, respectively. These findings indicate that Nrxns anterogradely regulate the postsynaptic nanoscopic architecture of glutamate receptors through competition and coordination of Nrxn ligands.
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Affiliation(s)
- Kazuya Nozawa
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Taku Sogabe
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Ayumi Hayashi
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Junko Motohashi
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Eriko Miura
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Itaru Arai
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Michisuke Yuzaki
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan.
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Leung HW, Foo G, VanDongen A. Arc Regulates Transcription of Genes for Plasticity, Excitability and Alzheimer’s Disease. Biomedicines 2022; 10:biomedicines10081946. [PMID: 36009494 PMCID: PMC9405677 DOI: 10.3390/biomedicines10081946] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/21/2022] [Accepted: 07/25/2022] [Indexed: 02/06/2023] Open
Abstract
The immediate early gene Arc is a master regulator of synaptic function and a critical determinant of memory consolidation. Here, we show that Arc interacts with dynamic chromatin and closely associates with histone markers for active enhancers and transcription in cultured rat hippocampal neurons. Both these histone modifications, H3K27Ac and H3K9Ac, have recently been shown to be upregulated in late-onset Alzheimer’s disease (AD). When Arc induction by pharmacological network activation was prevented using a short hairpin RNA, the expression profile was altered for over 1900 genes, which included genes associated with synaptic function, neuronal plasticity, intrinsic excitability, and signalling pathways. Interestingly, about 100 Arc-dependent genes are associated with the pathophysiology of AD. When endogenous Arc expression was induced in HEK293T cells, the transcription of many neuronal genes was increased, suggesting that Arc can control expression in the absence of activated signalling pathways. Taken together, these data establish Arc as a master regulator of neuronal activity-dependent gene expression and suggest that it plays a significant role in the pathophysiology of AD.
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Affiliation(s)
| | - Gabriel Foo
- Duke-NUS Medical School, Singapore 169857, Singapore
| | - Antonius VanDongen
- Duke-NUS Medical School, Singapore 169857, Singapore
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710, USA
- Correspondence:
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40
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Heuser JE. The Structural Basis of Long-Term Potentiation in Hippocampal Synapses, Revealed by Electron Microscopy Imaging of Lanthanum-Induced Synaptic Vesicle Recycling. Front Cell Neurosci 2022; 16:920360. [PMID: 35978856 PMCID: PMC9376242 DOI: 10.3389/fncel.2022.920360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 05/05/2022] [Indexed: 11/29/2022] Open
Abstract
Hippocampal neurons in dissociated cell cultures were exposed to the trivalent cation lanthanum for short periods (15–30 min) and prepared for electron microscopy (EM), to evaluate the stimulatory effects of this cation on synaptic ultrastructure. Not only were characteristic ultrastructural changes of exaggerated synaptic vesicle turnover seen within the presynapses of these cultures—including synaptic vesicle depletion and proliferation of vesicle-recycling structures—but the overall architecture of a large proportion of the synapses in the cultures was dramatically altered, due to large postsynaptic “bulges” or herniations into the presynapses. Moreover, in most cases, these postsynaptic herniations or protrusions produced by lanthanum were seen by EM to distort or break or “perforate” the so-called postsynaptic densities (PSDs) that harbor receptors and recognition molecules essential for synaptic function. These dramatic EM observations lead us to postulate that such PSD breakages or “perforations” could very possibly create essential substrates or “tags” for synaptic growth, simply by creating fragmented free edges around the PSDs, into which new receptors and recognition molecules could be recruited more easily, and thus, they could represent the physical substrate for the important synaptic growth process known as “long-term potentiation” (LTP). All of this was created simply in hippocampal dissociated cell cultures, and simply by pushing synaptic vesicle recycling way beyond its normal limits with the trivalent cation lanthanum, but we argued in this report that such fundamental changes in synaptic architecture—given that they can occur at all—could also occur at the extremes of normal neuronal activity, which are presumed to lead to learning and memory.
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Choquet D, Opazo P. The role of AMPAR lateral diffusion in memory. Semin Cell Dev Biol 2022; 125:76-83. [PMID: 35123863 DOI: 10.1016/j.semcdb.2022.01.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 12/17/2022]
Abstract
The accumulation of AMPARs to synapses is a fundamental step in Long-term potentiation (LTP) of synaptic transmission, a well-established cellular correlate of learning and memory. The discovery of a sizeable and highly mobile population of extrasynaptic AMPARs - randomly scanning the synaptic surface under basal conditions - provided a conceptual framework for a simplified model: LTP can be induced by the capture, and hence accumulation, of laterally diffusing extrasynaptic AMPARs. Here, we review the evidence supporting a rate-limiting role of AMPAR lateral diffusion in LTP and as consequence, in learning and memory. We propose that there are "multiple solutions" for achieving the diffusional trapping of AMPAR during LTP, mainly mediated by the interaction between interchangeable AMPAR auxiliary subunits and cell-adhesion molecules containing PDZ-binding domains and synaptic scaffolds containing PDZ-domains. We believe that this molecular degeneracy in the diffusional trapping of AMPAR during LTP serve to ensure the robustness of this crucial step in the making of memories. All in all, the role of AMPAR lateral diffusion in LTP is not only a conceptual leap in our understanding of memory, but it might also hold the keys for the development of therapeutics against disorders associated with memory deficits such as Alzheimer's disease.
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Affiliation(s)
- Daniel Choquet
- Interdisciplinary Institute for Neuroscience, CNRS, Univ. Bordeaux, IINS, UMR 5297, Bordeaux, France; Univ. Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, Bordeaux, France.
| | - Patricio Opazo
- UK Dementia Research Institute, Centre for Discovery Brain Sciences, University of Edinburgh, Chancellor's Building, Edinburgh Medical School, Edinburgh EH16 4SB, UK; Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia.
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Li S, Li L, Li J, Liang X, Song C, Zou Y. miR-203, fine-tunning neuroinflammation by juggling different components of NF-κB signaling. J Neuroinflammation 2022; 19:84. [PMID: 35413928 PMCID: PMC9006621 DOI: 10.1186/s12974-022-02451-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 03/29/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND miR-203 was first indicated in maintaining skin homeostasis and innate immunity. Aberrant expression of miR-203 was found associated with pathological progressions of immune disorders, cancers, as well as neurodegenerations. Recently, increasing data on miR-203 in regulating neuroinflammation and neuronal apoptosis has raised extensive concern about the biological function of this microRNA. METHODS Mouse model with ectopic miR-203 expression in the hippocampus was constructed by stereotactic injection of lentiviral expression vector of pre-miR-203. Association of miR-203 and mRNA of Akirin2, as well as the competition for miR-203 targeting between Akirin2 3'UTR and another recently characterized miR-203 target, 14-3-3θ, was verified using Dual-Luciferase Reporter Gene Assay and western blot. Microglia activation and pro-inflammatory cytokines expression in the hippocampus of mice overexpressing miR-203 was evaluated using immunohistochemistry analysis and western blot. Neuronal cell death was monitored using anti-caspase 8 in immunohistochemistry as well as TUNEL assay. Cognition of mice was assessed with a behavior test battery consisting of nesting behavior test, Barnes maze and fear conditioning test. RESULTS Akirin2, an activator of NF-κB signaling, was identified as a direct target of miR-203. By also targeting 14-3-3θ, a negative regulator of NF-κB signaling, miR-203 displayed an overall pro-inflammatory role both in vitro and in vivo. Promoted nuclear translocation of NF-κB and increased expression of proinflammatory cytokines were observed in cultured BV2 cells transfected with miR-203 mimics. Microglia activation and upregulation of NF-κB, IL-1β and IL-6 were observed in mouse hippocampus with overexpression of miR-203. In addition, promoted neuronal cell death in the hippocampus and impaired neuronal activities resulted in cognitive dysfunction of mice with ectopic miR-203 expression in the hippocampus. CONCLUSION A pro-inflammatory and neurodisruptive role of miR-203 was addressed based on our data in this study. Given the identification of Akirin2 as a direct target of miR-203 and the competition with 14-3-3θ for miR-203 targeting, together with the findings of other signaling molecules in NF-κB pathway as targets of miR-203, we proposed that miR-203 was a master modulator, fine-tunning neuroinflammation by juggling different components of NF-κB signaling.
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Affiliation(s)
- Shufang Li
- The Key Laboratory of Virology of Guangzhou, Jinan University, Guangzhou, China
| | - Linpeng Li
- The Key Laboratory of Virology of Guangzhou, Jinan University, Guangzhou, China
| | - Jieli Li
- The Key Laboratory of Virology of Guangzhou, Jinan University, Guangzhou, China
| | - Xiaosheng Liang
- The Key Laboratory of Virology of Guangzhou, Jinan University, Guangzhou, China
| | - Chao Song
- The Key Laboratory of Virology of Guangzhou, Jinan University, Guangzhou, China
| | - Yi Zou
- The Key Laboratory of Virology of Guangzhou, Jinan University, Guangzhou, China. .,Department of Biology, School of Life Science and Technology, Jinan University, Guangzhou, China.
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Gookin SE, Taylor MR, Schwartz SL, Kennedy MJ, Dell’Acqua ML, Crosby KC, Smith KR. Complementary Use of Super-Resolution Imaging Modalities to Study the Nanoscale Architecture of Inhibitory Synapses. Front Synaptic Neurosci 2022; 14:852227. [PMID: 35463850 PMCID: PMC9024107 DOI: 10.3389/fnsyn.2022.852227] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 03/08/2022] [Indexed: 11/13/2022] Open
Abstract
The nanoscale architecture of synapses has been investigated using multiple super-resolution methods, revealing a common modular structure for scaffolds, neurotransmitter receptors, and presynaptic proteins. This fundamental organization of proteins into subsynaptic domains (SSDs) is thought to be important for synaptic function and plasticity and common to many types of synapses. Using 3D super-resolution Structured Illumination Microscopy (3D-SIM), we recently showed that GABAergic inhibitory synapses exhibit this nanoscale organizational principle and are composed of SSDs of GABA A receptors (GABA A Rs), the inhibitory scaffold gephyrin, and the presynaptic active zone protein, RIM. Here, we have investigated the use of 3D-SIM and dSTORM to analyze the nanoscale architecture of the inhibitory synaptic adhesion molecule, neuroligin-2 (NL2). NL2 is a crucial mediator of inhibitory synapse formation and organization, associating with both GABA A Rs and gephyrin. However, the nanoscale sub-synaptic distribution NL2 remains unknown. We found that 3D-SIM and dSTORM provide complementary information regarding the distribution of NL2 at the inhibitory synapse, with NL2 forming nanoscale structures that have many similarities to gephyrin nanoscale architecture.
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Affiliation(s)
- Sara E. Gookin
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Matthew R. Taylor
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Samantha L. Schwartz
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Matthew J. Kennedy
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Mark L. Dell’Acqua
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Kevin C. Crosby
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
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Nikkar R, Esmaeili-Bandboni A, Badrikoohi M, Babaei P. Effects of inhibiting astrocytes and BET/BRD4 chromatin reader on spatial memory and synaptic proteins in rats with Alzheimer's disease. Metab Brain Dis 2022; 37:1119-1131. [PMID: 35244824 DOI: 10.1007/s11011-022-00940-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 02/21/2022] [Indexed: 10/18/2022]
Abstract
Communication between astrocytes and neurons has a profound effect on the pathophysiology of Alzheimer's disease (AD). Astrocytes regulate homeostasis and increase synaptic plasticity in physiological situations, however, they become activated during the progression of AD. Whether or not these reactions are supportive or detrimental for the central nervous system have not been understood yet. Considering epigenetic regulation of neuroinflammatory genes by chromatin readers, particularly bromodomain and extraterminal domain (BET) family, here we examined the effect of chronic co-inhibition of astrocytes metabolism (with fluorocitrate) and also BRD4 (with JQ1) on cognition deficit at early stages of AD. Forty adult male Wistar rats underwent stereotaxic cannulation for inducing AD by intrahippocampal injection of Aβ1-42 (4 μg/8 μl/rat). Then animals were divided into five groups of Saline+DMSO, Aβ + saline+DMSO, Aβ + JQ1, Aβ + FC (fluorocitrate), and Aβ + JQ1 + FC and received the related treatments. Two weeks later, spatial memory was recorded by Morris Water Maze (MWM), and the levels of phosphorylated cyclic-AMP response element binding protein (CREB), postsynaptic density 95 (PSD95), synaptophysin (SYP), and tumor necrosis factor-alpha (TNF-α) were measured in the hippocampus by western blotting and RT-qPCR. Administration of JQ1 significantly improved both acquisition and retrieval of spatial memory, which were evident by decreased escape latency and increased total time spent (TTS) in target quadrant, and significant rise in p-CREB, PSD95, and synaptophysin compared with Aβ + saline+DMSO group. In contrast, both groups receiving FC demonstrated memory decline, and reduction in p-CREB, PSD95 and synaptophysin in parallel with increase in TNF-α. Our data indicate that chronic inhibition of BRD4 significantly restores memory impaired by amyloid β partly via CREB signaling and upregulating synaptic proteins of PSD95 and synaptophysin. However, inhibition of astrocytes nullifies the memory-boosting effects of JQ1 and reduces CREB/PSD95/synaptophysin levels in hippocampus.
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Affiliation(s)
- Rastin Nikkar
- Cellular &Molecular Research Center, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran
- Neuroscience Research Center, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran
| | - Aghil Esmaeili-Bandboni
- Department of Medical Genetics, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran
- Medical Biotechnology Research Center, School of Paramedicine, Guilan University of Medical Sciences, Rasht, Iran
| | - Mahshid Badrikoohi
- Cellular &Molecular Research Center, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran
- Department of Physiology, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran
| | - Parvin Babaei
- Cellular &Molecular Research Center, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran.
- Neuroscience Research Center, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran.
- Department of Physiology, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran.
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Broadhead MJ, Bonthron C, Waddington J, Smith WV, Lopez MF, Burley S, Valli J, Zhu F, Komiyama NH, Smith C, Grant SGN, Miles GB. Selective vulnerability of tripartite synapses in amyotrophic lateral sclerosis. Acta Neuropathol 2022; 143:471-486. [PMID: 35305541 PMCID: PMC8960590 DOI: 10.1007/s00401-022-02412-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 02/23/2022] [Accepted: 03/09/2022] [Indexed: 12/12/2022]
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disorder. Separate lines of evidence suggest that synapses and astrocytes play a role in the pathological mechanisms underlying ALS. Given that astrocytes make specialised contacts with some synapses, called tripartite synapses, we hypothesise that tripartite synapses could act as the fulcrum of disease in ALS. To test this hypothesis, we have performed an extensive microscopy-based investigation of synapses and tripartite synapses in the spinal cord of ALS model mice and post-mortem human tissue from ALS cases. We reveal widescale synaptic changes at the early symptomatic stages of the SOD1G93a mouse model. Super-resolution microscopy reveals that large complex postsynaptic structures are lost in ALS mice. Most surprisingly, tripartite synapses are selectively lost, while non-tripartite synapses remain in equal number to healthy controls. Finally, we also observe a similar selective loss of tripartite synapses in human post-mortem ALS spinal cords. From these data we conclude that tripartite synaptopathy is a key hallmark of ALS.
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Sneve MA, Piatkevich KD. Towards a Comprehensive Optical Connectome at Single Synapse Resolution via Expansion Microscopy. Front Synaptic Neurosci 2022; 13:754814. [PMID: 35115916 PMCID: PMC8803729 DOI: 10.3389/fnsyn.2021.754814] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 12/17/2021] [Indexed: 12/04/2022] Open
Abstract
Mapping and determining the molecular identity of individual synapses is a crucial step towards the comprehensive reconstruction of neuronal circuits. Throughout the history of neuroscience, microscopy has been a key technology for mapping brain circuits. However, subdiffraction size and high density of synapses in brain tissue make this process extremely challenging. Electron microscopy (EM), with its nanoscale resolution, offers one approach to this challenge yet comes with many practical limitations, and to date has only been used in very small samples such as C. elegans, tadpole larvae, fruit fly brain, or very small pieces of mammalian brain tissue. Moreover, EM datasets require tedious data tracing. Light microscopy in combination with tissue expansion via physical magnification-known as expansion microscopy (ExM)-offers an alternative approach to this problem. ExM enables nanoscale imaging of large biological samples, which in combination with multicolor neuronal and synaptic labeling offers the unprecedented capability to trace and map entire neuronal circuits in fully automated mode. Recent advances in new methods for synaptic staining as well as new types of optical molecular probes with superior stability, specificity, and brightness provide new modalities for studying brain circuits. Here we review advanced methods and molecular probes for fluorescence staining of the synapses in the brain that are compatible with currently available expansion microscopy techniques. In particular, we will describe genetically encoded probes for synaptic labeling in mice, zebrafish, Drosophila fruit flies, and C. elegans, which enable the visualization of post-synaptic scaffolds and receptors, presynaptic terminals and vesicles, and even a snapshot of the synaptic activity itself. We will address current methods for applying these probes in ExM experiments, as well as appropriate vectors for the delivery of these molecular constructs. In addition, we offer experimental considerations and limitations for using each of these tools as well as our perspective on emerging tools.
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Affiliation(s)
- Madison A Sneve
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, United States
| | - Kiryl D Piatkevich
- School of Life Sciences, Westlake University, Hangzhou, China
- Westlake Laboratory of Life Sciences and Biomedicine, Westlake University, Hangzhou, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, China
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47
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McAlpin BR, Mahalingam R, Singh AK, Dharmaraj S, Chrisikos TT, Boukelmoune N, Kavelaars A, Heijnen CJ. HDAC6 inhibition reverses long-term doxorubicin-induced cognitive dysfunction by restoring microglia homeostasis and synaptic integrity. Theranostics 2022; 12:603-619. [PMID: 34976203 PMCID: PMC8692908 DOI: 10.7150/thno.67410] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 11/09/2021] [Indexed: 02/07/2023] Open
Abstract
Breast cancer is the most common female malignancy in both the developed and developing world. Doxorubicin is one of the most commonly used chemotherapies for breast cancer. Unfortunately, up to 60% of survivors report long-term chemotherapy-induced cognitive dysfunction (CICD) characterized by deficits in working memory, processing speed and executive function. Currently, no therapeutic standard for treating CICD exists. Here, we hypothesized that treatment with a blood-brain barrier permeable histone deacetylase 6 (HDAC6) inhibitor can successfully reverse long-term doxorubicin-induced cognitive dysfunction. Methods: The puzzle box test and novel object/place recognition test were used to assess cognitive function following a therapeutic doxorubicin dosing schedule in female mice. Mitochondrial function and morphology in neuronal synaptosomes were evaluated using the Seahorse XF24 extracellular flux analyzer and transmission electron microscopy, respectively. Hippocampal postsynaptic integrity was evaluated using immunofluorescence. Hippocampal microglia phenotype was determined using advanced imaging techniques and single-nucleus RNA sequencing. Results: A 14-day treatment with a blood-brain barrier permeable HDAC6 inhibitor successfully reversed long-term CICD in the domains of executive function, working and spatial memory. No significant changes in mitochondrial function or morphology in neuronal synaptosomes were detected. Long-term CICD was associated with a decreased expression of postsynaptic PSD95 in the hippocampus. These changes were associated with decreased microglial ramification and alterations in the microglia transcriptome that suggest a stage 1 disease-associated microglia (DAM) phenotype. HDAC6 inhibition completely reversed these doxorubicin-induced alterations, indicating a restoration of microglial homeostasis. Conclusion: Our results show that decreased postsynaptic integrity and a neurodegenerative microglia phenotype closely resembling stage 1 DAM microglia contribute to long-term CICD. Moreover, HDAC6 inhibition shows promise as an efficacious pharmaceutical intervention to alleviate CICD and improve quality of life of breast cancer survivors.
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Affiliation(s)
- Blake R McAlpin
- Laboratories of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Rajasekaran Mahalingam
- Laboratories of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Anand K Singh
- Laboratories of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Shruti Dharmaraj
- Laboratories of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Taylor T Chrisikos
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Nabila Boukelmoune
- Laboratories of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Annemieke Kavelaars
- Laboratories of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Cobi J Heijnen
- Laboratories of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- ✉ Corresponding author: Cobi J. Heijnen, Ph.D., 6565 MD Anderson Blvd., Zayed Building Z8.5034, Houston, Texas 77030, Phone 713-563-0162,
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48
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Gorka F, Daly S, Pearson CM, Bulovaite E, Zhang YP, Handa A, Grant SGN, Snaddon TN, Needham LM, Lee SF. A Comparative Study of High-Contrast Fluorescence Lifetime Probes for Imaging Amyloid in Tissue. J Phys Chem B 2021; 125:13710-13717. [PMID: 34883017 PMCID: PMC7615715 DOI: 10.1021/acs.jpcb.1c07762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Optical imaging of protein aggregates in living and post-mortem tissue can often be impeded by unwanted fluorescence, prompting the need for novel methods to extract meaningful signal in complex biological environments. Historically, benzothiazolium derivatives, prominently Thioflavin T, have been the state-of-the-art fluorescent probes for amyloid aggregates, but their optical, structural, and binding properties typically limit them to in vitro applications. This study compares the use of novel uncharged derivative, PAP_1, with parent Thioflavin T as a fluorescence lifetime imaging probe. This is applied specifically to imaging recombinant α-synuclein aggregates doped into brain tissue. Despite the 100-fold lower brightness of PAP_1 compared to that of Thioflavin T, PAP_1 binds to α-synuclein aggregates with an affinity several orders of magnitude greater than Thioflavin T; thus, we observe a specific decrease in the fluorescence lifetime of PAP_1 bound to α-synuclein aggregates, resulting in a separation of >1.4 standard deviations between PAP_1-stained brain tissue background and α-synuclein aggregates that is not observed with Thioflavin T. This enables contrast between highly fluorescent background tissue and amyloid fibrils that is attributed to the greater affinity of PAP_1 for α-synuclein aggregates, avoiding the substantial off-target staining observed with Thioflavin T.
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Affiliation(s)
- Felix Gorka
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
- Department of Physics, Philipps-University Marburg, Marburg, 35032, Germany
| | - Sam Daly
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Colin M Pearson
- Department of Chemistry, Indiana University, Bloomington, Indiana, 47405, USA
| | - Edita Bulovaite
- Genes to Cognition Programme, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Yu P. Zhang
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Anoushka Handa
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Seth G. N. Grant
- Genes to Cognition Programme, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Thomas N. Snaddon
- Department of Chemistry, Indiana University, Bloomington, Indiana, 47405, USA
| | - Lisa-Maria Needham
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
| | - Steven F. Lee
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
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Hosokawa T, Liu PW. Regulation of the Stability and Localization of Post-synaptic Membrane Proteins by Liquid-Liquid Phase Separation. Front Physiol 2021; 12:795757. [PMID: 34975543 PMCID: PMC8716852 DOI: 10.3389/fphys.2021.795757] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 11/17/2021] [Indexed: 12/01/2022] Open
Abstract
Synaptic plasticity is a cellular mechanism of learning and memory. The synaptic strength can be persistently upregulated or downregulated to update the information sent to the neuronal network and form a memory engram. For its molecular mechanism, the stability of α-amino-3-hydroxyl-5-methyl-4-isoxazolepropionate-type glutamate receptor (AMPAR), a glutamatergic ionotropic receptor, on the postsynaptic membrane has been studied for these two decades. Since AMPAR is not saturated on the postsynaptic membrane during a single event of neurotransmitter release, the number and nanoscale localization of AMPAR is critical for regulating the efficacy of synaptic transmission. The observation of AMPAR on the postsynaptic membrane by super-resolution microscopy revealed that AMPAR forms a nanodomain that is defined as a stable segregated cluster on the postsynaptic membrane to increase the efficacy of synaptic transmission. Postsynaptic density (PSD), an intracellular protein condensate underneath the postsynaptic membrane, regulates AMPAR dynamics via the intracellular domain of Stargazin, an auxiliary subunit of AMPAR. Recently, it was reported that PSD is organized by liquid-liquid phase separation (LLPS) to form liquid-like protein condensates. Furthermore, the calcium signal induced by the learning event triggers the persistent formation of sub-compartments of different protein groups inside protein condensates. This explains the formation of nanodomains via synaptic activation. The liquid-like properties of LLPS protein condensates are ideal for the molecular mechanism of synaptic plasticity. In this review, we summarize the recent progress in the properties and regulation of synaptic plasticity, postsynaptic receptors, PSD, and LLPS.
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50
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Aleksejenko N, Heller J. Super-resolution imaging to reveal the nanostructure of tripartite synapses. Neuronal Signal 2021; 5:NS20210003. [PMID: 34737894 PMCID: PMC8536832 DOI: 10.1042/ns20210003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/24/2021] [Accepted: 09/28/2021] [Indexed: 12/13/2022] Open
Abstract
Even though neurons are the main drivers of information processing in the brain and spinal cord, other cell types are important to mediate adequate flow of information. These include electrically passive glial cells such as microglia and astrocytes, which recently emerged as active partners facilitating proper signal transduction. In disease, these cells undergo pathophysiological changes that propel disease progression and change synaptic connections and signal transmission. In the healthy brain, astrocytic processes contact pre- and postsynaptic structures. These processes can be nanoscopic, and therefore only electron microscopy has been able to reveal their structure and morphology. However, electron microscopy is not suitable in revealing dynamic changes, and it is labour- and time-intensive. The dawn of super-resolution microscopy, techniques that 'break' the diffraction limit of conventional light microscopy, over the last decades has enabled researchers to reveal the nanoscopic synaptic environment. In this review, we highlight and discuss recent advances in our understanding of the nano-world of the so-called tripartite synapses, the relationship between pre- and postsynapse as well as astrocytic processes. Overall, novel super-resolution microscopy methods are needed to fully illuminate the intimate relationship between glia and neuronal cells that underlies signal transduction in the brain and that might be affected in diseases such as Alzheimer's disease and epilepsy.
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Affiliation(s)
- Natalija Aleksejenko
- School of Biotechnology and National Institute for Cellular Biotechnology (NICB), Dublin City University, Glasnevin, Ireland
| | - Janosch P. Heller
- School of Biotechnology and National Institute for Cellular Biotechnology (NICB), Dublin City University, Glasnevin, Ireland
- Queen Square Institute of Neurology, University College London, London, United Kingdom
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